Learning management systems and cloud file hosting services: A study on students’ acceptance

The aim of this paper is to investigate the motivations that lead higher education students to replace several Learning Management Systems (LMS) services with cloud file hosting services for information sharing and collaboration among them. The research approach is based on the Technology Acceptance Model (TAM). More specifically, the model is devoted to identifying barriers and enablers to the acceptance of these technologies. A questionnaire comprising three factors (Attitude toward using technology, Perceived ease of use and Perceived usefulness) was applied to a sample consisting of 121 higher education students. Results show that the perceived ease of use of cloud file hosting services is above that of LMS tools and services and that cloud file hosting services presented higher levels of perceived usefulness than standard learning management tools. In addition, attitude toward using cloud file hosting services is well above that of using LMS tools.     

Measurement-based study on the relation between users’ watching behavior and network sharing in P2P VoD systems

P2P-based Video on Demand (P2P VoD) systems can provide higher quality video services than P2P live systems. However, owing to the unavailability of open source codes, the characteristics of P2P VoD systems have not been fully explored. For this purpose, in this paper, we first implemented reverse engineering to the protocols of two most popular VoD systems used in China. Peers’ watching behavior and network sharing were then studied through the measured buffer messages. Based on our study, we found that uploading-only peers were more than downloading peers, and smooth-watching peers were more than randomly-seeking peers in the current P2P VoD systems. This finding is significantly different from the existing P2P-based file dissemination systems and the results obtained in the previous work on VoD systems. Furthermore, this study revealed the relations between watching behavior and network sharing. It has been observed that randomly-seeking peers will provide more regular as well as rare chunks than smooth-watching peers. A simple mathematical model was established to analytically demonstrate the relation between the watching index (WI) distribution and network-sharing profile, and this relation was also validated by our measured data.     

A dynamic framework for integrated management of all types of resources in P2P systems

Traditional Peer-to-Peer (P2P) systems were restricted to sharing of files on the Internet. Although some of the more recent P2P distributed systems have tried to support transparent sharing of other types of resources, like computer processing power, but none allow and support sharing of all types of resources available on the Internet. This is mainly because the resource management part of P2P systems are custom designed in support of specific features of only one type of resource, making simultaneous access to all types of resources impractical. Another shortcoming of existing P2P systems is that they follow a client/server model of resource sharing that makes them structurally constrained and dependent on dedicated servers (resource managers). Clients must get permission from a limited number of servers to share or access resources, and resource management mechanisms run on these servers. Because resource management by servers is not dynamically reconfigurable, such P2P systems are not scalable to the ever growing extent of Internet. We present an integrated framework for sharing of all types of resources in P2P systems by using a dynamic structure for managing four basic types of resources, namely process, file, memory, and I/O, in the same way they are routinely managed by operating systems. The proposed framework allows P2P systems to use dynamically reconfigurable resource management mechanisms where each machine in the P2P system can at the same time serve both as a server and as a client. The pattern of requests for shared resources at a given time identifies which machines are currently servers and which ones are currently clients. The client server pattern changes with changes in the pattern of requests for distributed resources. Scalable P2P systems with dynamically reconfigurable structures can thus be built using our proposed resource management mechanisms. This dynamic structure also allows for the interoperability of different P2P systems.     

Perceptual control architecture for cyber–physical systems in traffic incident management

Based on Perceptual Control Theory, we study the problem of unified modeling for incompatible approaches of Cyber–Physical Systems (CPSs). Inspired by the effective organization of living systems structure accommodating heterogeneous information processing and environmental interaction, we propose Perceptual Control Architecture of CPSs, and take Traffic Incident Management systems as the modeling research carrier. Throughout the structure of Traffic Incident Management systems, the hierarchical negative feedback is constituted by perceptual and behavioral loops to ensure a mechanism of intelligence behavior. The internal representation is categorized into two intelligent spaces: physical-reflex space and cyber-virtual space. In physical-reflex space, the sensing-actuation mapping of objective world is built, through four levels of distributed traffic infrastructure. In cyber-virtual space, subjective decision using Bayesian reasoning network is defined by three levels: principles, interrelated factors and situation assessment. Through evaluation of field operation in Dalian, the Traffic Incident Management under the developed architecture shows a considerable reduction in response time as well as assessment inaccuracy. The test results explicated the effectiveness of the architecture on integrating complex Cyber–Physical functions. Besides transportation systems, the modeling approach could be a well-defined unified architecture applied to other CPSs.     

The “problem” in and of management information systems

Management Information Systems uncritically draws upon a number of disciplines for its theoretical framework. In doing so it has imported a host of ontological, epistemological and behavioral assumptions which have shaped the theories, technologies and practices of information system analysis, design and implementation. This has taken place without careful reflection upon the historical emergence of these assumptions or upon the context within which attempts are made to operationalize them. This paper argues that the Management Information Systems field is in need of researching itself. It proposes that through a combination of genealogical and ethnographic research methodologies, the historical emergence of theoretical constructs and the organizational context within which information systems operate should be critically examined. In the following analysis, the historical emergence of the “problem” as a generic construct in the Management Information System literature is examined and contrasted to the manner in which a group of manufacturing managers defined problems within their organizational context. A critical tension is revealed which suggests that information systems researchers, analysts and designers need to at least broaden their assumption about the nature of organizational reality, human behavior, information processing and problem solving.     

When carrots and sticks meet: A mixed-methods study on internet taxi drivers’ job engagement in the IT-driven sharing economy

Information technology (IT)-enabled taxi services facilitate people's lives. However, little is known about how Internet taxi employees are motivated and how motivation relates to their job engagement. Using a mixed-methods design, this research explores intrinsic motivators and the effects of external regulations on intrinsic motivation and job engagement. The qualitative study identified three context-specific intrinsic motivators: stress reduction, self-efficacy, and job autonomy. A follow-up quantitative research revealed the significance of external regulations in determining intrinsic motivation and job engagement. The study contributes to knowledge by emphasizing the role of intrinsic motivators and the significance of both monetary incentives and punishment.     

Mean–variance relationship of the number of flows in traffic aggregation and its application to traffic management

We consider the mean–variance relationship of the number of flows in traffic aggregation, where flows are divided into several groups randomly, based on a predefined flow aggregation index, such as source IP address. We first derive a quadratic relationship between the mean and the variance of the number of flows belonging to a randomly chosen traffic aggregation group. Note here that the result is applicable to sampled flows obtained through packet sampling. We then show that our analytically derived mean–variance relationship fits well those in actual packet trace data sets. Next, we present two applications of the mean–variance relationship to traffic management. One is an application to detecting network anomalies through monitoring a time series of traffic. Using the mean–variance relationship, we determine the traffic aggregation level in traffic monitoring so that it meets two predefined requirements on false positive and false negative ratios simultaneously. The other is an application to load balancing among network equipments that require per-flow management. We utilize the mean–variance relationship for estimating the processing capability required in each network equipment.     

How users’ participation affects reputation management systems: The case of P2P networks

In this work human factor is explored by means of agent based simulation and analyzed in the framework of a reputation management system (RMS), within a peer-to-peer (P2P) network. Reputation is about evaluating an agent’s actions and other agents’ opinions about those actions, reporting on those actions and opinions, and reacting to that report, thus creating a feedback loop. This social mechanism has been successfully used to classify agents within normative systems. The systems rely on the feedbacks given by the members of the social network in which the RMS operates. Reputation can thus be seen as an endogenous and self produced indicator, created by the users for the users’ benefit. This implies that users’ participation and collaboration is a key factor for the effectiveness a RMS.     

Why do people file share unlawfully? A systematic review,meta-analysis and panel study

Unlawful digital media sharing is common and believed to be extremely damaging to business. Understanding unlawful file sharers' motivations offers the opportunity to develop business models and behavioral interventions to maximize consumers' and businesses’ benefit. This paper uses a systematic review of unlawful file sharing research, and the Theory of Planned Behavior, to motivate a large-scale panel study in which initial determinants were used to predict subsequent behavior. A meta-analysis found Attitudes, Subjective Norms and Perceived Behavioral Control were all associated with unlawful file sharing. Media type and demographic differences in the importance of Perceived Behavioral Control were found and attributed to more accurate evaluation of familiar activities, i.e., greater experience increases the influence of Perceived Behavioral Control but age does not.The panel study confirmed that greater past experience was associated with Perceived Behavioral Control and Intention. We conclude that past experience increases the efficacy of the Theory of Planned Behavior and specifically Perceived Behavioral control in predicting behavior, contrary to some widely held beliefs about the role of experience. The role of experience is therefore crucial to understanding people's choices. Practically, improving social approval, positive evaluation and access to lawful media should reduce unlawful behavior.     

Taxonomy of attacks and defense mechanisms in P2P reputation systems—Lessons for reputation system designers

Robust and credible reputation systems are essential for the functionality of Peer-to-Peer (P2P) applications. However, they themselves are susceptible to various types of attacks. Since most current efforts lack an exploration of a comprehensive adversary model, we try to fill in this gap by providing a thorough view of the various credibility threats against a decentralized reputation system and the respective defense mechanisms. Therefore, we explore and classify the types of potential attacks against reputation systems for P2P applications. We also study and classify the defense mechanisms which have been proposed for each type of attack and identify conflicts between defense mechanisms and/or desirable characteristics of credible reputations systems. We finally propose a roadmap for reputation system designers on how to use the results of our survey for the design of robust reputation systems for P2P applications.     

Ant colony optimization inspired resource discovery in P2P Grid systems

It is a challenge for the traditional centralized or hierarchical Grid architecture to manage the large-scale and dynamic resources, while providing scalability. The Peer-to-Peer (P2P) model offers a prospect of dynamicity, scalability, and availability of a large pool of resources. By integrating the P2P philosophy and techniques into a Grid architecture, P2P Grid system is emerging as a promising platform for executing large-scale, resource intensive applications. There are two typical resource discovery approaches for a large-scale P2P system. The first one is an unstructured approach which propagates the query messages to all nodes to locate the required resources. The method does not scale well because each individual query generates a large amount of traffic and the network quickly becomes overwhelmed by the messages. The second one is a structured approach which places resources at specified locations to make subsequent queries easier to satisfy. However, the method does not support multi-attribute range queries and may not work well in the network which has an extremely transient population. This paper proposes and designs a large-scale P2P Grid system which employs an Ant Colony Optimization (ACO) algorithm to locate the required resources. The ACO method avoids a large-scale flat flooding and supports multi-attribute range query. Multiple ants can be employed to improve the parallelism of the method. A simulator is developed to evaluate the proposed resource discovery mechanism. Comprehensive simulation results validate the effectiveness of the proposed method compared with the traditional unstructured and structured approaches.

A proxy-based integrated cache consistency and mobility management scheme for client–server applications in Mobile IP systems

In this paper, we investigate a proxy-based integrated cache consistency and mobility management scheme for supporting client–server applications in Mobile IP systems with the objective to minimize the overall network traffic generated. Our cache consistency management scheme is based on a stateful strategy by which cache invalidation messages are asynchronously sent by the server to a mobile host (MH) whenever data objects cached at the MH have been updated. We use a per-user proxy to buffer invalidation messages to allow the MH to disconnect arbitrarily and to reduce the number of uplink requests when the MH is reconnected. Moreover, the user proxy takes the responsibility of mobility management to further reduce the network traffic. We investigate a design by which the MH’s proxy serves as a gateway foreign agent (GFA) as in the MIP Regional Registration protocol to keep track of the address of the MH in a region, with the proxy migrating with the MH when the MH crosses a regional area. We identify the optimal regional area size under which the overall network traffic cost, due to cache consistency management, mobility management, and query requests/replies, is minimized. The integrated cache consistency and mobility management scheme is demonstrated to outperform MIPv6, no-proxy and/or no-cache schemes, as well as a decoupled scheme that optimally but separately manages mobility and service activities in Mobile IPv6 environments.     

Sensors and controllers location in distributed systems—A survey

A survey of the field of optimal sensors and/or controllers location for dynamical distributed parameter systems modelled by partial differential equations is presented. The recent contributions in this field are grouped according to the main goal for which the location problem is developed, namely: system identification, state estimation, and optimal control. In order to pose the sensors and controllers location problem, the semigroup approach for modelling distributed linear systems is briefly reviewed together with its equivalent (infinite dimensional) and approximate (finite dimensional) Fourier expansion representations. After presenting a concise general review of the several methods considered in the current literature, a classification of methods is also proposed. The main classifying factor concerns the use of N-modal approximation schemes, and the different stages of the optimization procedure in which they are required.     

Can competitive advantage be achieved through knowledge management? A case study on SMEs

Unlike most Knowledge Management (KM) studies which focus on large enterprises, this study focuses on SMEs in Malaysia which represent 99.2% of the total business establishments, the largest percentage of establishments in the country. The tridimensional relationship between KM practices, technological innovation (TI) and competitive advantage (CA) was examined in this case study. Survey approach was conducted to gather data from managers of the manufacturing SMEs and 195 samples were usable for statistical analysis using Partial-Least-Square Structural Equation Modeling (PLS-SEM)-Artificial Neural Network (ANN). The use of the combined PLS-SEM and ANN analysis can provide a significant methodological contribution and substantial impacts to the world of expert and intelligent systems and could be the next methodological research paradigm. Findings validated that KM has a direct positive and significant relation with both TI and CA; while TI positively and significantly affects CA. Most outstandingly, the mediating role of TI that connects KM and CA has been proven to be positive and significant. This paper utilizes samples that were collected from Malaysian SMEs only; therefore the findings cannot be generalized to represent the larger firms. Nevertheless, conclusions garnered from the present research can help both practitioners of the manufacturing SMEs and scholars in implementing the correct KM strategies, so that both TI and CA can be enhanced and improved.     

A comparative study on particle�Cfluid interactions in micro and nanofluids of aluminium oxide

Stable dispersions of micro and nanosized Al₂O₃ particles in ethylene glycol are prepared with the aid of sonication. The temperature dependant acoustic properties such as ultrasonic velocity, adiabatic compressibility, attenuation and acoustic impedance are studied and reported in this paper. In microfluids the particle–fluid interaction is observed to decrease with increase of concentration of particles whereas in nanofluids it is observed to increase up to the critical concentration (0.6 Wt%) and above which the particle–particle interaction dominates due to agglomeration of particles. A range of concentration with significant particle–fluid interaction is identified for effective nanofluid applications.     

Optimal allocation and maintenance of multi-state elements in series–parallel systems with common bus performance sharing

This article considers the optimal allocation and maintenance of multi-state elements in series–parallel systems with common bus performance sharing. The surplus performance from a sub-system can be transmitted to any other sub-system which is experiencing performance deficiency. The amount that can be transmitted is subjected to a random transmission capacity. In order to increase the system availability, maintenance actions can be performed during the system lifetime and the system elements can be optimally allocated into the sub-systems. In this paper, we consider the element allocation and maintenance simultaneously in order to minimize the total maintenance cost subject to the pre-specified system availability requirement. An algorithm based on universal generating function is suggested to evaluate the system availability and the genetic algorithm is explored to solve the optimization problem. Numerical experiments are presented to illustrate the applications.     

A study on facility location–allocation problem in mixed environment of randomness and fuzziness

In logistics system, facility location–allocation problem, which can be used to determine the mode, the structure and the form of the whole logistics system, is a very important decision problem in the logistics network. It involves locating plants and distribution centers, and determining the best strategy for allocation the product from the plants to the distribution centers and from the distribution centers to the customers. Often uncertainty may be associated with demand, supply or various relevant costs. In many cases, randomness and fuzziness simultaneously appear in a system, in order to describe this phenomenon; we introduce the concept of hybrid variable and propose a mixed-integer programming model for random fuzzy facility location–allocation problem. By expected value and chance constraint programming technique, this model is reduced to a deterministic model. Furthermore, a priority-based genetic algorithm is designed for solving the proposed programming model and the efficacy and the efficiency of this method and algorithm are demonstrated by a numerical example. Till now, few has formulated or attacked the FLA problems in the above manner. Furthermore, the techniques illustrated in this paper can easily be applied to other SCN problems. Therefore, these techniques are the appropriate tools to tackle other supply chain network problems in realistic environments.     

Towards an automatic engineering change management in smart product-service systems – A DSM-based learning approach

The rapid development and implementation of smart, connected products (SCPs) in the engineering field has triggered a promising manufacturing paradigm of servitization, i.e. smart product-service systems (Smart PSS). As a complex solution bundle in both system and product level, its engineering change management differs from the existing ones mainly in two aspects. Firstly, massive in-context stakeholder-generated/product-sensed data during usage stage can be leveraged to enable its success in a data-driven manner. Secondly, the digitalized services, consisting of both hardware and software solutions, can also be changed in a more flexible way other than the physical components alone. Nevertheless, scarcely any work reports on how to conduct engineering change in such context, let alone a systematic approach to support the automatic generation of its change prediction or recommendation. Aiming to fill these gaps, this work proposes an occurrence-based design structure matrix (DSM) approach together with a three-way based cost-sensitive learning approach for automatic engineering change management in the Smart PSS environment. This informatics-based research, as an explorative study, overcomes the subjectivity and tedious assessment of the experts in the conventional approaches, and can offer useful guidelines to the manufacturing companies for managing their engineering changes for product-service innovation process.     

Observations on measure and lowness for Δ 2 P

Assuming thatk≥2 and Δ _k ^/P does not have p-measure 0, it is shown that BP · Δ _k ^/P =Δ _k ^/P . This implies that the following conditions hold if Δ ₂ ^P does not have p-measure 0:

Comments on ‘Fixed modes and local feedbacks in interconnected systems’

Two statements concerning fixed modes made by Caloyannis and Fessas are shown to be unnecessarily restrictive.