Privacy-preserving scheme for mobile ad hoc networks.

This paper proposes a decentralized trust establishment protocol for mobile ad hoc networks (MANETs), where nodes establish security associations. In order to achieve privacy and security, we use homomorphic encryption and polynomial intersection so as to find the intersection of two sets. The first set represents a list of recommenders of the initiator and the second set is a list of trusted recommenders of the responder. The intersection of the sets represents a list of nodes that recommend the first node and their recommendations are trusted by the second node. In our experimental results we show that our scheme is effective even if there are 30 trusted nodes

Dynamics, robustness and fragility of trust

Trust is often conveyed through delegation, or through recommendation. This makes the trust authorities, who process and publish trust recommendations, into an attractive target for attacks and spoofing. In some recent empiric studies, this was shown to lead to a remarkable phenomenon of *adverse selection*: a greater percentage of unreliable or malicious web merchants were found among those with certain types of trust certificates, then among those without. While such findings can be attributed to a lack of diligence in trust authorities, or even to conflicts of interest, our analysis of trust dynamics suggests that public trust networks would probably remain vulnerable even if trust authorities were perfectly diligent. The reason is that the process of trust building, if trust is not breached too often, naturally leads to power-law distributions: the rich get richer, the trusted attract more trust. The evolutionary processes with such distributions, ubiquitous in nature, are known to be robust with respect to random failures, but vulnerable to adaptive attacks. We recommend some ways to decrease the vulnerability of trust building, and suggest some ideas for exploration.Comment: 17 pages; simplified the statement and the proof of the main theorem; FAST 200

Disparity between the Programmatic Views and the User Perceptions of Mobile Apps

User perception in any mobile-app ecosystem, is represented as user ratings of apps. Unfortunately, the user ratings are often biased and do not reflect the actual usability of an app. To address the challenges associated with selection and ranking of apps, we need to use a comprehensive and holistic view about the behavior of an app. In this paper, we present and evaluate Trust based Rating and Ranking (TRR) approach. It relies solely on an apps' internal view that uses programmatic artifacts. We compute a trust tuple (Belief, Disbelief, Uncertainty - B, D, U) for each app based on the internal view and use it to rank the order apps offering similar functionality. Apps used for empirically evaluating the TRR approach are collected from the Google Play Store. Our experiments compare the TRR ranking with the user review-based ranking present in the Google Play Store. Although, there are disparities between the two rankings, a slightly deeper investigation indicates an underlying similarity between the two alternatives

Supply Chain Governance Mechanisms, Green Supply Chain Management, and Organizational Performance

While firms understand that implementing green supply chain management (GSCM) is important, they seem uncertain about how to manage their green initiatives by looking beyond their own facilities. Building a green supply chain requires the participation of all partner firms across the supply chain. However, partner firms are different in size, situation, capabilities, and even industries. Thus, encouraging them to participate in green initiatives is difficult. Many small and medium enterprises (SMEs) hesitate to comply with green initiatives as they require a substantial amount of investment. This study empirically examines the causal relationship between the partnership governance mechanism and the success of GSCM. Based on transaction-cost economics theory (i.e., opportunism) and relational perspectives (i.e., trust) as the theoretical background, this study found that governance mechanisms between suppliers and manufacturers are positively related to GSCM performance. It showed that formal governance is important in the process-management side, while relational governance is critical for sharing knowledge in GSCM. The implications of the study results provide strategic insights on how the choice of governance mechanism affects GSCM performance and thus a firm’s competitiveness

The Structure and Dynamics of Schools and Business: Do They Face Similar Issues?

The main aims of the report are to: (1) gain a better understanding of key economic forces shaping choices available to schools; (2) build up our practical knowledge of how other organisations deal with the kinds of issues facing schools; and (3) bridge the gap between the view that economics has nothing useful to say about how to organise education and the view that education is just another business and should be treated as such. The report draws on analogies from the business world to highlight parallels between the operating environment facing schools and businesses. It also identifies some important features of schooling which do not have a strong parallel in the business world, which suggests care needs to be taken not to draw too much from any individual example.

Barcelona hotel employees and their conception of fair work. An exploratory study

Purpose - Sustainable Development Goals (SDG) 5 and 8, respectively, indicate that decent work and gender equality are challenges that business organizations must face in order to achieve the social well-being and sustainable development of communities. Considering these goals, the present article aims to define the concept of fair work and examine the current degree of knowledge among staff in the hotel sector in Barcelona about the indicators of the Fair Labor Responsible Hotels (HJLR) certification. Design/methodology/approach - A mixed methodology is used to analyze the primary data. A survey of 248 employees is complemented by nine semi-structured interviews with experts, general managers and heads of department of independently owned hotels and national and international chains. Findings - The results show that this certification is necessary for the economic and social sustainability of the hospitality sector and to raise awareness that fair work is an urgent need. However, these currently tend to be little more than artificial actions. Originality/value - The paper aims to emphasize the perspective of real actors in hotel industry about the actors' considerations of fair work to enhance the actors' job involvement and satisfaction

Deriving safety cases for hierarchical structure in model-based development

Model-based development and automated code generation are increasingly used for actual production code, in particular in mathematical and engineering domains. However, since code generators are typically not qualified, there is no guarantee that their output satisfies the system requirements, or is even safe. Here we present an approach to systematically derive safety cases that argue along the hierarchical structure in model-based development. The safety cases are constructed mechanically using a formal analysis, based on automated theorem proving, of the automatically generated code. The analysis recovers the model structure and component hierarchy from the code, providing independent assurance of both code and model. It identifies how the given system safety requirements are broken down into component requirements, and where they are ultimately established, thus establishing a hierarchy of requirements that is aligned with the hierarchical model structure. The derived safety cases reflect the results of the analysis, and provide a high-level argument that traces the requirements on the model via the inferred model structure to the code. We illustrate our approach on flight code generated from hierarchical Simulink models by Real-Time Worksho