This New Articles Channel contents the latest articles published in Inderscience's distinguished academic, scientific and professional journals.
An energy-aware load balancing algorithm to perform computation type application processes in a cluster of servers
A cluster of servers is getting scalable and widely used in various types of applications. It is critical to reduce the electric energy consumed by servers in a cluster to realise eco society. In this paper, we newly propose an improved delay time based (IDTB) algorithm to reduce the total electric energy consumption of a cluster and to more efficiently utilise the computation resources for performing application processes in a cluster. In the IDTB algorithm, a load balancer estimates the state of each server just by using responses from processes and without additionally communicating with servers to collect states of the servers. We evaluate the IDTB algorithm compared with the basic round-robin (RR), improved power consumption laxity based (IPCLB), and delay time based (DTB) algorithms. We show the total electric energy consumption of a cluster and response time of each process can be reduced in the IDTB algorithm.
Secure and structured IoT smart grid system management
The Internet of Things (IoT) has been developing rapidly and inspiring numerous applications that can improve daily life. Among these, smart grid systems are expected to efficiently distribute energy and help address the energy shortage problem. However, grid data and information from heterogeneous embedded devices may result in security and communication problems in an IoT environment. Even in the situation where low-level information causes interoperability problems, the devices should be able to communicate with each other in a safe and efficient manner without a server or human intervention. In this paper, we propose a security-based context-aware smart grid system using an energy usage data aggregation and context awareness. Our proposal allows for intelligent decision-making and provides efficient smart grid system management based on machine knowledge. Using our proposed method, a smart grid system can provide robust and secure services, which can defend the system against various outside attacks.
Design and implementation of an IoT-based e-learning testbed
Owing to the opportunities provided by the internet, people are taking advantage of e-learning courses and many research efforts have been dedicated to the development of e-learning systems. So far, many e-learning systems are proposed and used practically. However, in these systems the e-learning completion rate is low. One of the reasons is the low study desire and motivation. In this work, we design and implement an IoT-based e-learning testbed using Raspberry Pi mounted on Raspbian. We analyse the performance of Optimised Link State Routing (OLSR) and Wired Equivalent Privacy (WEP) protocol in an indoor scenario. For evaluation we considered throughput, delay and jitter metrics. The experimental results show that the nodes in the testbed were communicating smoothly.
A review of data management and protocols for vehicular networks
In recent years, with the development of vehicular technology, vehicular communication has increasingly become a crucial and rising area. Creating an accident-free environment is the foremost goal of taking a real interest in this new research field. Some progress has been made in this area, new architectures, protocols and implementations of Vehicular Ad Hoc Network (VANET) have been made to supply Intelligent Transportation Services (ITS). The vehicle-to-vehicle communications play a vital role in vehicular networks, so we present a comprehensive overview of data management in this paper in order to explore the present research status with its main problems in vehicular communication. We describe the protocol of vehicular networks and the various types of data managed in that environment, also we analyse the challenges we face right now.
Enhanced secure low-level reader protocol based on session key update mechanism for RFID in IoT
Radio Frequency Identification (RFID) is at the core of the IoT (Internet-of-Things) technology. The security risks associated with RFID are also accompanied by a growing number of advantages. This paper focuses on the security of the Low Level Reader Protocol (LLRP) released by EPCglobal and designs an enhanced secure mechanism for LLRP that consists of the handshake protocol of the authentication and session key update protocols. The encryption is applied to the communication of the entire LLRP protocol; therefore, the session key should be regularly updated. Because the requirements for session key update are different under different scenarios, a two-round key update protocol and a four-round key update protocol are designed to ensure the security of the protocol. Two types of key update methods with different difficulty coefficients are developed to meet practical requirements. This paper concludes with a performance evaluation of the mechanism.
Relationship between collaboration and innovativeness: a case study in an innovative organisation
Collaboration shapes the culture of an innovative organisation and relates to its innovativeness, understood as a set of factors under control of the organisation that affect its ability to innovate. In order to verify the relationship between collaboration and innovativeness, a case study was conducted in an organisation that has a unique expertise in innovation. The research method was centred on content analysis of interviews with 16 respondents from three functional areas in three distinct hierarchical levels. The findings reveal that the organisation is able to sustain collaboration despite strong disagreement. The balance between autonomy (self-reliance) and interdependence (sharing), supported by close ties and goodwill (selflessness), among other factors, strengthened its social capital and thus supported its innovativeness. A theoretical framework of the relationship between collaboration factors and innovativeness is proposed.
Causal relationships between organisational learning and performance in the Spanish hotel industry: the managers' perception in times of economic crisis
The present empirical study aimed to analyse the ways in which Spanish hotel establishments learn and whether their hotel managers could improve their organisational performance with the implementation of a suitable learning process in a situation of economic crisis. After reviewing the literature, a structural equation model was developed based on a survey of 147 hotel establishments in the region of Madrid in order to contrast the proposed hypothesis. The results revealed that hotel establishments' managers can improve their performance through organisational learning, drawing information from both external and internal drivers thanks to the existence of cultural and technological enablers. The conclusions of the study contribute to the scientific understanding of the subject researched and at the same time may encourage hotel managers to regard organisational learning processes as a key element for improving performance.
Innovation in business education - the new way of learning at the Adidas Group Learning Campus
The key question of this paper is which components have to be considered when transforming an organisation into a learning organisation that attracts and retains the new generation of employees. To answer this question, a conceptual framework is developed, based on an extensive literature review. Additionally, the authors introduce how Adidas, as one of the world's top sports brands, is managing such a transformation. Data were gained from direct observations of the project on-site and expert meetings, as well as from analysis of internal company documents. This results in an extension of the conceptual framework by adding case specific characteristics. Hence, the purpose of this paper is to deliver a model that can be used as an orientation in today's corporate environment to follow all steps of the learning transformation in proper sequence and to consider all relevant elements. One finding is that companies have to be aware of the demands of new learners, which needs to be a leading principle for companies that implement a learning transformation. In subsequent processes, the organisation has to create clear objectives, implement a suitable corporate culture and establish learning spaces, followed by launching and promoting all the various ways of learning.
Can multicultural experience stimulate creativity? The moderating role of regulatory focus
Innovation is crucial to the success of organisations and is a core capability for their long-term survival. Creativity is the starting point of innovation. A number of studies have found that multicultural experiences can stimulate creativity. Nonetheless, the boundary conditions of this influence have yet to be fully elucidated. This study investigated whether one's regulatory focus moderates the relationship between multicultural experience and creativity. We adopted an experimental approach based on the manipulation of multicultural experience and regulatory focus with 120 students (study 1) and 120 executives (study 2) as participants. The results of evaluating their creativity indicated that multicultural experience exerts a significant influence on creativity. Furthermore, regulatory focus moderates the relationship between multicultural experience and creativity. These findings' on multicultural learning and creativity have important implications for human resource management and global learning.
Spatiality in higher education: a case study in integrating pedagogy, community engagement, and regional development
Higher educational institutions (HEIs) are expected to contribute to local economies and the working life through collaboration and regional development. Increasing demands and diminishing resources call for innovative solutions. We discuss the benefits of integrating education and regional development in HEIs through spatiality. We build on community engagement, knowledge transfer, spatiality and the Triple Helix; identifying a HEI's knowledge and people flows. We apply the frame to a case study of a university of applied sciences in Finland. Results suggest that there are a number of ways in which a HEI can collaborate with local industries and strengthen its regional impact without significant structural trade-offs and while supporting pedagogy. The results have implications for higher educational institutions, particularly, concerning the agile, transportable educational space concept. The study raises an important issue related to the assumptions of what makes a university: physical presence versus knowledge flows.
The phenomenon of information-communication technology in the homes of four-year-old preschool children in Slovenia
We live in an era defined by creating, conveying, sharing and storing vast amounts of information and the phenomenon of information-communication technology (ICT). Its overwhelming presence affects mainly the youngest members of our society - children. Therefore, authors decided to investigate to what extent four-year-old preschool children use ICT at home, how often they access it, ICTs influences on their development and their attitude towards ICT. Authors based on their study on data gathered with anonymous surveying of 130 parents whose children attend kindergarten. They also searched for differences according to children's gender and parents' level of education, toy industry market and family habitus. In addition, they investigated if ICT usage affects the nature of childhood and if using ICT influences the occurrence of the digital divide. They also include recommendations and guidelines for preschool educators. Authors conclude that children like to use ICT, but yet do not overuse it.
Social networking: how small organisations are using Facebook and Twitter in engaging customers
Social networking sites, such as Facebook, Twitter, LinkedIn or Google+, allow organisations to create profiles and become active members, small organisations have started incorporating these strategies into their public relations strategy. For large organisations have used these sites to engage more with their consumers and strengthen their existing brands; however, little is known about how small organisations are taking advantage of the social networking popularity. This qualitative study examines 55 small organisations in Cyprus and Greece on how they use these social networking sites to advance their organisation's PR and marketing programs and increase engagement with their customers. The results highlight the importance of social networking as a platform to engage and connect with their consumers and their consideration as a social media management tool. Careful planning and research will greatly benefit small organisations as they attempt to develop social networking relationships and increase engagement with their customers.
How technologies are changing the social relationships in the shopping experience?
This paper investigates the impact of the innovations held by the introduction of advanced technologies into the points of sale. In particular, it explores the sense of sociality emerging while integrating social networks, with emphasis on the quality of social interactions while shopping. The aims of this paper is to investigate the impact among social relationships during the purchasing process (including need of relatives' or friends' presence), relationships with vendors, eWOM and trust in technology on the attitude towards the use of these technologies as supporting tool while shopping. The study is based on a quantitative analysis involving 331 young consumers, analysed through the structural equation model. Findings show the extent to which these technological innovations are able to replace the traditional face-to-face interactions in terms of consumer-to-consumer and consumer-to-vendor ones.
Hotels and online travel agencies: power or trust for a competitive long-term relationship
The aim of this paper is to analyse the features of the relations between hotels and online travel agencies, with a particular regard to the issue of trust, which is widely recognised as a key factor for fostering customer-vendor relations and sustaining market share in socially distant relationships, such as online hotel booking. A multiple case study approach has been chosen, through 30 in-depth and semi-structured interviews to three, four and five-stars Italian hotel managers. In terms of results, four different kinds of relationships have been observed, depending on how information as a resource and contractual power may be balanced.
Engaging consumers on social media: empirical evidence from the communications analysis of a CSR oriented company
The purpose of this paper is to show how corporate social responsibility (CSR) communication on social media is actually implemented and managed in business practice by a coffee company in Italy with a proved track record in CSR related activities. Consistent with the explorative aim of the study, this paper employs a case study approach and it adopts a sensemaking-sensegiving framework. An analysis was carried out of the communication on social media by interviewing three key respondents and employing a content analysis technique in order to study the communication on Facebook and Twitter. Results show that even if a company is CSR oriented, communication on social media does not focus on social and environmental issues. The result is confirmed by the interviews which underline how difficult it is to create engagement and to create a two-way dialogue with stakeholders about CSR issues on social media. The paper ends by suggesting several recommendations for further CSR communication implementation of the company analysed and for business practice in general.
Challenges of social media marketing - an explorative international study of hotels
With the worldwide increased usage of social media, organisations are experiencing great pressure to implement social media into their existing marketing strategies. Due to this development, social media has rapidly become an important marketing tool. The study focuses on social media marketing implementation, with the aim to develop an increased understanding of the challenges concerning how hotels adapt social media into their marketing activities by investigating social media marketing usage in hotels. The result suggests that most hotels are reactive in their social media usage and do not actively seek interaction, and that individual knowledge needs to be spread throughout organisations to a greater extent in order to achieve interaction with customers in social media channels.
Reconceptualising buyer behaviour in the digital era: an emergent journey
This paper undertakes a conceptual examination of the emergence of digital marketing in recent decades. It identifies a number of key trends in consumer behaviour and manners in which the medium is evolving. The argument progresses to examine and challenge predominant conceptualisations of the buyer behaviour process and considers how these have been recast in the advent of digital technologies. This provides the backdrop to develop a novel diagrammatic representation of digital marketing buyer behaviour processes which can be tested empirically. The model is illustrated through the use of a vignette which points up the complexities which the model aims to represent. The paper concludes with an appeal for the continued development, modelling and empirical testing of the evolving world of digital buyer behaviour.
Transient flow of viscous compressible fluid past a heated cylinder
In the present investigation, we have considered the effect of the enthalpy transfer on the growth of the boundary layer flow of compressible fluid past a heated cylinder. The governing equations of the boundary layer are transformed into a convenient form by a method of transformed coordinates. The transformed equations are then solved numerically using the finite difference method for all time regime, perturbation solutions for small time regime, and the asymptotic solutions for large time regime. The solutions are obtained for different values of the Mach number, M0 and the surface temperature parameter while Prandtl number equals 0.7 and the ratio of specific heats equals 1.4 and shown the effects on the local shear-stress and the rate of enthalpy transfer at the surface of the cylinder as well as on the streamlines and isoenthapies. Some numerical values of the point of separation that took place at different time steps as well as different values of surface temperature parameter and Mach number at the steady state are given in tabular form.
Evaluation of go-kart aerodynamic efficiency using CFD, RBF mesh morphing and lap time simulation
The study featured in this paper presents a CFD, RBF mesh morphing and lap time simulation-based analysis method to investigate the effect of aerodynamic drag on go-kart performance. A bodywork design exploration is performed, employing an automatic response surface optimisation, to evaluate effects of its shape on aerodynamic penetration. The effect of driver size is explored as well by adapting the mesh according to a parametric mannequin positioning workflow. Results of the design exploration process highlight a very good optimisation of the baseline configuration with respect to aerodynamic efficiency. On the other hand, driver size reduction produces a noticeable drag decrease in the order of 4.5%. To translate registered drag changes into performance variations, an in-house lap time simulator based on a lumped parameter model is adopted. Lap time for two different karting circuits are simulated in high and low drag configurations resulting in lap time variations in the order of 0.1/0.2 sec.
An investigation and comparative analysis on marine gas turbine rotor blade with cooling holes using FEA
Cooling technology plays a critical role in operating the turbine blade at elevated temperature. The aim of this research work is to keep the entire blade cool enough and thus maintaining the temperature gradients within the blade to an acceptable level. Several cooling techniques have been proposed for the cooling of turbine blades and one such technique is to have radial holes to pass high velocity cooling air along the blade span. Four different models have been developed consisting of a solid blade and blades with varying number of holes. These models have been designed using CATIA and analysed using ANSYS 14.5. Two turbine blade materials namely INCONEL X-750 and NIMONIC-105 have been chosen for comparative analysis. It has been found that NIMONIC-105 might be better suited material for turbine blades. From the analysis, it has been found that the temperature distribution, Von-Misses stress and total deformation are within the safe limits and are optimum for the turbine blade with 13 holes made of NIMONIC-105.
Calibration of single cylinder four stroke computer control engine by changing inlet manifold dimensions with bio-based tri-fuel
This paper describes an experimental investigation of the performance variations and emissions of the single cylinders of internal thread-intake port diesel engines under both steady-state and motored engine conditions using bio-based tri-fuels. The tri-fuel is assortment of diesel, turpentine blend and acetylene gas. The acetylene gas is produced from lime stone (CACO3) and the turpentine oil obtained from pine tree. The intension of the swirl is done by creating threads internally in order to create the turbulence by swirl. The performance of tri-fuel has been analysed experimentally single cylinder direct injection and compression ignition engine with diesel and turpentine blend as primary fuel and acetylene inducted as secondary gaseous fuel, i.e., diesel and the turpentine (40% turpentine and 60% diesel). The results showed that the blend and the acetylene gas flow rate of 3 litre/minute offered higher brake thermal efficiency between 1% and 3% than that of diesel base line operation.
Mixed convection flow over a slender cylinder due to the combined effects of thermal and mass diffusion
This paper deals with the similarity solution of double-diffusive mixed convection flow over a vertical slender cylinder due to the combined effects of thermal and mass diffusion. Local similarity method has been used to transform governing nonlinear partial differential equations into ordinary differential equations. With the help of a set of suitable similarity transformations, the nonlinear coupled partial differential equations governing select phenomena (such as flow, thermal and concentration field) have been reduced to a set of nonlinear coupled ordinary differential equations. Numerical solution of system of nonlinear ordinary differential equations are derived using an implicit finite difference scheme along with quasilinearisation technique. The significant observations of the study are as follows: 1) strong effect of buoyancy parameter λ on the flow and thermal field; 2) strong influence of Prandtl number (Pr) and Sherwood number (Sc) on heat transfer and mass transfer respectively.
Operational efficiency and its determinants of Indian food and beverages industries: a DEA approach
The operational efficiency of the food and beverages industry is determined by identifying the technical and scale efficiencies by applying data envelopment analysis (DEA) models. A set of 46 companies with average data collected for the year 2005-2006 to 2009-2010 is used for the study. The analysis begins with a benchmark study, followed by identification of peers and their followers. Nine firms emerge as peers. The slacks of the inefficient firms are identified. Regression analysis is used to estimate the causal relationship between operational efficiency and the other chosen variables. Analyses of peer firms are conducted to identify the influencing variables of the peer firms. The first stage DEA analysis reveals that the inefficiencies such as scale and technical inefficiencies exist in the Indian food and beverages industry and a majority of inefficient firms are operating in the increasing returns to scale region. The second stage analysis using the OLS regression to identify the determinants of these inefficiencies reveals that current ratio and financial assets to total assets are contributing significantly to the inefficiencies.
Suppliers' corporate ability and consumer evaluations of a manufacturer
This study explores consumer perceptions of supply chain partners. In particular, we analyse whether a supplier's corporate ability affects consumer evaluations of a manufacturer. We also examine the moderating effect of a supplier's market position, either the top-dog (strong) or underdog (weak) position. Using a vignette-based experiment, we find that a supplier's high corporate ability does not affect how consumers evaluate the manufacturer. However, a supplier's low corporate ability leads consumers to devalue the manufacturer. We also find that the effect of a supplier's corporate ability is moderated by the supplier's market position: the link between a supplier's low corporate ability and consumers' negative evaluations of a manufacturer becomes stronger when the supplier is perceived as in a top-dog position.
Linkage between total quality and supply chain management practices and operational performance: a review
This paper investigate the scope of total quality (TQM) and supply chain management (SCM) practices linkage to enhance the operational performance of an organisation. The selected research articles related to TQM and SCM from year 1984 to 2014 have been reviewed. The review has adopted study wise (empirical, conceptual and literature review), industry wise, country wise and year wise distribution, which leads to the identified research gaps through literature review. The literature review reveals that TQM and SCM are two different concepts that share most common goal which is customer satisfaction, but also have differences. However, TQM and SCM should be linked to have synergetic effect on operational performance of an organisation. This study will help the future researchers and professionals to preview the TQM and SCM from different angles for linking of the approaches. The study also highlight, a view that, how quality and supply chain practices can be customised according to the nature of products or services. This paper will be helpful for practicing managers, by offering a different view of linkage between TQM and SCM for enhancing operational performance.
A new stochastic demand model for dual-sourcing supply chain considering disruption risk
In this paper, we propose a single period-product model with two supply channels when disruption is feasible in wholesaler-retailer channels considering back-orders and lost sales. Here we define a maximisation model regarding disruptions in dual channels and sensitivity analysis on the parameters has been done based on it. We test our proposed model by several numerical examples and finally used contour curves to show disruption effects on order quantity and ordering channel selection.
A two-step multi-objective mathematical model for nurse scheduling problem considering nurse preferences and consecutive shifts
The nurse scheduling problem (NSP) has received special attention during the recent decades. The difficulty of generating tables manually alongside the shortage of nurses and prohibition of outsourcing nurses has led to hectic schedules in which assigning three consecutive shifts (i.e., 24 hour shift) to a nurse could be seen. Furthermore, nurses' preferences are usually neglected because the concentration is on meeting the nursing requirements. In this paper, we propose a multi-objective mathematical model in which we tackle the main inefficiency of the system (i.e., three consecutive shifts). We also try to maximise nurses' preferences. In addition to the presentation of a new mathematical model, we use the novel method of augmented epsilon constraint to generate several tables. To deal with the complexity of NSP, we use a two-step approach. We find the efficient solutions over the Pareto set, among which we select the best table.
Relationship between marketing program and brand loyalty: Is there an influence of gender?
This study identifies and investigates the key elements of marketing mix and its influence on brand loyalty. Existing branding models often reveal significant weaknesses due to the lack of empirical testing and narrow focus. This study develops a model to examine the effects of marketing elements on brand loyalty and differences across gender. With data collected from Saudi Arabia, the model is tested by a two-stage process. The first stage assesses the reliability and validity of measurement model. The second stage tests the various structural models. Findings reveal that price is the only significant factor affecting brand loyalty for females, while for the males, price, quality, and promotion are all significant. Results have implications for marketers in their efforts at building brand loyalty and targeting a specific gender. The study makes an original contribution by demonstrating the robustness of the alternative measurement model of brand loyalty.
What leads Saudi Arabian consumers to purchase counterfeit luxury products?
This study examines factors that affect attitude and intention to buy counterfeit or fake branded luxury products in seeking social status among 303 Saudi consumers. Data were conveniently collected via a questionnaire survey in Jeddah, Saudi Arabia, and were analysed using descriptive statistics, hierarchical multiple regression and structural equation modelling. Results show that social status insecurity influences consumer attitude and purchase intention towards such luxury products. It also indicates that status consumption and value consciousness have no effect on consumer attitudes towards counterfeit branded luxury products. However, there is a statistically significant positive interaction or moderation influence of value consciousness on consumption of luxury products to gain social status and on attitude towards counterfeit branded luxury products, indicating more favourable attitudes and purchase intention towards counterfeit branded luxury products. Some practical implications of the findings are given.
The effect of communication strategy on the relationship between strategy execution (organisational level) and organisational performance: a middle level managers' perspective at higher education institutions
This study aimed to analyse the effect of communication strategy on the relationship between strategy execution and organisational performance of universities. The proposed constructs of independent variables were organisational level of analysis (organisational size, organisational structure, organisational culture, and reward system), and communication strategy. Specifically, the communication strategy was tested as a moderator. In other words, the effects of these three constructs were measured against organisational performance. The study was developed based on general system theory and contingency theory. The total respondents were 236 and all of them are working with the higher education institutions in Palestine. Based on SEM-PLS to analyse the data, the study found that specific strategy execution with a specific communication strategy produced better organisational performance. Finally the findings provide invaluable implication to theory and practice on execution of strategy of service based institutions like universities.
The link between creativity and credibility with sustainable growth of entrepreneurial firms: evidence from Sri Lanka
This paper shows how creativity and credibility of entrepreneurial firms in Sri Lanka contribute to sustained growth in constantly turbulent and hostile emerging market conditions characterised by high uncertainty and risk owing to political and economic instability, internal ethnic conflicts and changes in social values. This is a suitable context to test the significance of individual and corporate credibility on the survival and growth of entrepreneurial firms operating in different market environments. This study applied a mixed research methodology by combining case research and a questionnaire based large survey on the owners and top managers of 158 successful entrepreneurial firms operating in Sri Lanka. This research found that in a turbulent and hostile emerging market context, creativity and credibility significantly influence entrepreneurial firm growth. The findings offer entrepreneurs in emerging markets important insights into growth strategies for surviving and thriving in often-hostile market conditions.
A feedback model for an effective performance appraisal system
The paper discusses a performance feedback model for an effective performance appraisal system in organisations. Most organisations today lack an effective performance appraisal system primarily because the way performance feedback is given and received promotes a culture that discourages an effective performance appraisal (PA) system. An effective performance feedback model can play a key role in an organisation by enhancing employee engagement, motivation and job satisfaction. Keeping in view the problems that organisations face owing to poor feedback culture, the paper proposes and outlines a new performance feedback model that involves a positive quality-centred feedback approach relying on employee assertion and reinforcement. Unlike the conventional limitation-centred performance feedback model that highlights the gap areas and shortcomings of the employees, the new model takes its sustenance from a positive feedback culture.
Corporate failure prediction model in Indonesia: revisiting the Z-scores, discriminant analysis, logistic regression and artificial neural network
We investigate the accuracy of several corporate failure prediction models, namely the original Altman's Z-score and Z˝-score, discriminant analysis, logistic regression and artificial neural network (ANN) by studying Indonesian firms. Using hand-collected data of forced delisting and healthy listed firms in Indonesia stock exchange, our results show that our ANN model has the highest accuracy among other models, respectively, followed by Z˝-score, logistic regression model, discriminant analysis model and the original Z-score. In addition, among these models, we also find that the original Z-score has the smallest type I error, or it is the most sensitive model, whereas Z˝-score has the smallest type II error, or it is the most specific model. Thus, in the view of efficiency, even though those models are very simple and were developed more than 30 years ago, the predictive ability of their combination is still pertinent to predict corporate failure in Indonesia.
Enhanced MAC protocol for designing a wireless sensor network based on a single LEO Picosatellite
In this paper, we address the design of a wireless sensor network (WSN) using a single low earth orbit (LEO) satellite. The satellite, as small as a Picosatellite, requires employment of a very simple payload whereas all the complexity is brought back to the relay nodes (RNs), which are connected directly to the Picosatellite using a multiple access protocol. An improvement protocol to enhance the performance of Slotted Aloha, based on collision avoidance after first successful transmission, is proposed. We establish a mathematical model for evaluating the performance of the proposed protocol with collision avoidance termed as Slotted AlohaCA. Two appropriate performance measures are evaluated: Throughput and Energy efficiency. In the model, each RN has M packets to send during the visibility period of the Picosatellite. The proposed scheme approaches the maximum throughput of 100% for high value of M and hence improves significantly the energy efficiency compared with the traditional Slotted Aloha protocol owing to collision avoidance.
MRBNS: a new energy-efficient communication scheme in low power wireless networks
A new energy-efficient communication scheme has been proposed based on a novel source coding technique along with the idea of silent communication, so that the frequencies of occurrences of different symbols in the encoded message become very asymmetric. Keeping the symbol period with the highest frequency of occurrence as silent during transmission, we achieve substantial savings of transmitter and receiver energies by using a hybrid FSK-ASK modulation/demodulation technique. We also design the corresponding protocols for transmission and reception of messages and evaluate their performances to compare with other existing techniques. Our results demonstrate that for additive white Gaussian noise in channels, on an average, the transmitter side energy is reduced by about 53%, while at the receiver side there is about 17.2% savings. Due to the savings of both transmitter and receiver energies, our proposed scheme is particularly suitable for multi-hop communication in low power wireless networks.
Energy-efficient activation of nodes and radios in multi-radio WLAN mesh networks
In multi-radio WLAN mesh networks (WMNs), it is an effective way to achieve energy saving through on-demand activation of network nodes and radios, that is, scheduling nodes on/off and switching radios on/off according to the current traffic demand. In this paper, we study the problem of joint node scheduling and radio switching for energy efficiency, which aims to minimise the power consumption of the network. We first present a mathematical model based on integer linear programming (ILP). Then, we propose an efficient heuristic algorithm, which iteratively finds routing paths for all mesh access points (MAPs) and activates as few nodes and radios as possible, while satisfying their traffic demand. Moreover, we also consider the dynamics of the traffic demand, and propose a fast update algorithm to adjust the activation of partial nodes and radios. Finally, extensive simulations are conducted to assess the effectiveness and efficiency of our proposed algorithms.
MRF-based multi-view action recognition using sensor networks
Action recognition has become an active area of research in the field of video surveillance. In this paper, a local space-time constraint Markov random fields (MRFs) model is proposed for the recognition of multi-view action based on the posture's articulation points from the sensor networks in the smart family space. The position distribution under different views and the time continuity of the posture sequence are used as the random field to label the corresponding action classes. Experimental results show that the proposed model can accurately recognise the actions of objects under multi-views in the family environment and requires low running time.
A survey of intrusion detection systems in smart grid
Smart grid has emerged as an option-loaded, efficient replacement of the out-of-date power grid infrastructure. However, with the introduction of smart grid systems and the many benefits that they bring along, we now face new security vulnerabilities. This paper offers a survey of intrusion detection in smart grid and aims to analyse the existing approaches and methods proposed thus far, in trying to tackle security vulnerabilities within smart grid systems.
Optimisation and formability study of AA5052 through incremental sheet forming
In this paper, a well-organised and optimised methodology, Taguchi-grey relational analysis, is integrated with the experimental results of incremental sheet forming (ISF) process while considering multiple response characteristics. This tactic combines the orthogonal array design of the experiment with grey relational analysis. The main objective of this study is to attain improved formability and depth at fracture and reduced downward force. Grey relational theory is applied to explore the optimum process parameters which optimise the response characteristics. The experiment is executed using Taguchi's orthogonal L9 array (34). Each experiment is executed under diverse settings of input parameters. From the response table, the grey relational grade value for each level of experiment is duly noted. From the analysis, the best combination of forming parameters is found out. These experimental results prove that the suggested method efficiently and effectively improves the forming performance of ISF process.
Hybrid optimisation model for blind spot reduction in heavy vehicles
The road accidents are common nowadays and the visibility of the driver is the prime factor in such accidents. Many lives as well as money have been lost during accidents. Reduction of blind spot area improves the area of visibility of the driver which leads towards the reduction of the accidents. This paper aims to optimise the blind spot area by considering the design parameters used in the design of rear view mirror in heavy vehicles. This is achieved by using a hybrid multi-criteria decision making (MCDM) approach by integrating complex proportional assessment of alternatives (COPRAS) technique and entropy measurement. The effectiveness of the developed model is proved by a case study conducted in a public transport corporation located in the southern part of India.
Testing and performance analysis of micro encapsulated rice bran distilled fatty acid
This work deals with the performance analysis of incorporation of a phase change material (PCM) in building construction as micro capsules instead of macro encapsulation. Micro capsules are used in various applications, particularly in construction for passive exchange of heat across walls and roof. Completion of basic study leads rice bran distilled fatty acid-grade-A (RBDFA)/melamine formaldehyde (MF) as the suitable core PCM and covering material, respectively for the test site. Micro RBDFA capsule's thermo-physical properties were studied using thermo gravimetric analysis (TGA), Fourier transform infrared spectrophotometer (FT-IR) and differential scanning calorimeter (DSC) and all test results satisfied the basic requirements. Two model blocks were constructed, one with macro encapsulated RBDFA roof and another one with micro encapsulated RBDFA roof. Temperature variation inside the model blocks was observed. The results indicated that, inclusion of micro encapsulated RBDFA in construction gives positive effect to maintain less temperature variation at indoor that is 5-7°C less than ambient condition.
Assignment of machines in cell layout using modified artificial bee colony algorithm
Cellular manufacturing (CM) is now an established international practice to integrate: equipment, people, and systems into 'focused factories', 'mini-businesses' or 'cells' with clear customers, responsibilities and boundaries. The major element in exploiting the benefits of CM is efficient layout designs. In this paper, problem of machine assignment is considered in a cellular layout. The focus is on the intra-cell machines allocation, because the inter-cell material flows should be minimal in CM. The modified artificial bee colony (MABC) algorithm is proposed to solve the layout problem. The algorithm tackles one cell at a time with a maximum of nine machines, which will be assigned into a 3 × 3 grid space according to the ranking result. This problem involves five parts and five quantitative demand periods are considered. To examine the performance of the proposed MABC, datasets are taken from the literature and the results are compared with those of other approaches. The proposed MABC provides an optimal layout exactly.
Performance of consistent through-thickness electric potential distribution for Euler-Bernoulli piezoelectric beam finite elements
An accurate piezoelectric beam finite element analysis essentially requires appropriate assumptions of the field variables involved in the formulation. The conventional Euler-Bernoulli piezoelectric beam finite elements assume an independent linear through-thickness distribution of electric potential in a physical piezoelectric layer which is actually nonlinear due to induced potential effects. Here, a consistent through-thickness potential distribution in a physical piezoelectric layer derived from the electrostatic equilibrium equation is tested for its accuracy against the linear assumption. This consistent potential field contains, in addition to the conventional linear terms, a higher order term coupled with bending strain. Thus, this finite element, though employing higher order potential, does not increase the number of nodal electrical degrees of freedom. It is shown that the performance of the present formulation with consistent through-thickness potential is insensitive to the geometric configuration and material properties of the beam cross-section, unlike the conventional formulations.
Ant-based job shop scheduling with genetic algorithm for makespan minimisation on identical machines
The ant-based optimisation techniques have been used in various problems and could be used in job shop scheduling. The application of ant-based method in job shop scheduling is to find out the sequence of jobs with low time complexity. A new ant-based job shop scheduling algorithm with genetic algorithm is proposed using support, which generates a scheduling of jobs with low waited time for the processes while scheduling the jobs. The support in the new genetic algorithm is inversely proportional to the time complexity. The genetic algorithm with support function is proposed to find out the path in which all the processes have to service with resources. The proposed algorithm produces optimal scheduling in which all processes have to wait minimum time. The problem is to reduce the waiting time of all the processes.
Scheduling problem solving using genetic and greedy algorithms
Scheduling is an important tool for manufacturing and engineering, where it can have a major impact on the productivity of a process. In manufacturing, the purpose of scheduling is to minimise the production time and costs. Production scheduling aims to maximise the efficiency of the operation and reduce costs. The following approaches are used to solve the job shop problem. We keep all of our machines well-maintained to prevent any problems, but there is no way to completely prevent down-time. We can work to get our batch sizes as small as is reasonably possible while also reducing the setup time of each batch. This allows us to eliminate a sizable portion of each part waiting while the rest of the parts in the batch are being machined. In this paper, we propose the production scheduling problem solving using genetic and greedy algorithms with sequence dependant setup times considering the minimisation of the maximum completion time.
Optimisation of cutting parameters in CNC turning of EN-19 using tungsten carbide
Efficient turning of high performance EN series material can be achieved through proper selection of turning process parameters to minimise surface roughness and maximise the material removal rate. This present paper outlines an experimental study to optimise and study the effects of process parameters in CNC turning on surface roughness of EN19/AISI4140 (medium carbon steel) work material in dry environment conditions. The orthogonal array, signal to noise ratio and regression technique were employed to study the performance characteristics in CNC turning operation. Four machining parameters were chosen as process parameters. They are cutting speed, feed rate, tool nose radius and depth of cut. The experimentation plan was designed using Taguchi's L9 orthogonal array (OA) and Minitab-16 statistical software. Optimal values of process parameters for desired performance characteristics were obtained by Taguchi design of experiment. Moreover prediction models had been developed with the help of regression analysis to find the effect of cutting parameters.
Optimisation of swept angles for airfoil NACA 6-series
A NACA 6-series is one of the most commonly used commercial passenger aircraft, which is of subsonic and transonic type. This series, a laminar flow type is taken for our study. In this paper the straight wing and the swept back wings are designed using a suitable tool and it is simulated by using CFD software. FLUENT software is used to analyse the different swept angles of 0°, 25°, 30°, 35°, 40° and 45° for different mach numbers ranging from 0.6 to 1.2. Based on these results the drag coefficient (CD ) and lift coefficient (CL ) are plotted. The values for the straight and swept wings indicate that there is a reduction in drag coefficient. Then thus by means of optimisation factor the swept angle is optimised for the NACA 6-series air foil. By the help of the optimising factor we have found that 35° will be more efficient and it is the best choice for a high speed aircraft, because this wing minimises fuel consumption and thereby by remarkably reducing wave drag during flight thus reducing the cost of flight and increase the range of aircraft and at the same time it ensures a safe take-off and a smooth landing.
Mechanical testing of epoxy bonded eco friendly natural fibre composite material
The development of high-performance materials made from natural resources is increasing worldwide. The greatest challenge in working with natural fibre reinforced plastic composites is their large variation in properties and characteristics. Composite's properties are influenced by a number of variables, including the fibre type, environmental conditions (where the plant fibres are sourced), processing methods, and any modification of the fibre. The need to have composite materials that are renewable has lead to materials scientists researching on natural fibres. To minimise environmental pollution, research into rice husk, saw dust and cashew nut dust has been on for a period of time now. Rice husk, cashew nut shell dust and saw dust are easily available in huge amount. We have been considering as raw material for composite production these material are renewable sources. In this work, we have to prepare three different sample composite materials with epoxy resin. As the percentage of filler content increases the mechanical properties of tensile strength, torsion test and hardness test and impact strength were checked. In general, RH/CN/SD composite could be considered as a potential source of low cost, natural fibre for composites.
Mechanical behaviour and analysis of advanced polymer-based Kevlar-49 composite material
The fatigue behaviour of reinforced composites is complex and the present knowledge of fatigue study still needs extensive investigation of the micromechanical composite behaviour. In fibre reinforced composites mechanical properties are highly dependent on their compositions, the matrix type as well as the volume fraction of the reinforcement and their arrangements such as random orientation and distribution, which increase the complexity in the study of fatigue damage behaviour. There exist several classes of models to predict the fatigue life or the fatigue degradation of fibre reinforced composites but there exists so far no fatigue model that can be applied to a wide range of fibre reinforced composites. Thus, modifications of fatigue models are always needed in accordance with the micromechanical behaviour of different fibre/matrix composites. In this project the fatigue failure is rectified by using polymer-based Kevlar composite material. The design and fabrication involves the design of polymer matrix like as fibre and resin, hardener etc. Kevlar-49 is chosen for as fabricating material to carry out this work. The fabrication set up is made by hand lay-up and it is demonstrated satisfactorily.
Effect of starch treatment and hybridisation on the mechanical properties of natural fibre composites
In this investigation, studies are carried out on the mechanical properties of hybrid polymer composites. Hybrid composites can reach a better combination of both artificial and natural fibre properties. Different weight percentages of jute fibres were hybridised with coconut sheath to produce the composites through compression moulding. Composites were produced using untreated and treated fibres. Fibre surfaces were treated with trichloro(vinyl)silane and starch solutions. Inter-laminar shear strength (ILSS) and flexural tests were conducted on the composites. Results show that jute hybridisation yields significant enhancement in the coconut sheath composite. Composites with starch treated fibres shows higher flexural strength. Scanning electron microscopy of the fracture surface revealed agglomeration of fibres in the fibre-matrix interface, which helped increasing flexural strength.