Providing Reliable Data Transport for Dynamic Event Sensing in Wireless Sensor Networks

In this paper, we propose a Loss Tolerant Reliable (LTR) data transport mechanism for dynamic Event Sensing (LTRES) in WSNs. In LTRES, a reliable event sensing requirement at the transport layer is dynamically determined by the sink. A distributed source rate adaptation mechanism is designed, incorporating a loss rate based lightweight congestion control mechanism, to regulate the data traffic injected into the network so that the reliability requirement can be satisfied. An equation based fair rate control algorithm is used to improve the fairness among the LTRES flows sharing the congestion path. The performance evaluations show that LTRES can provide LTR data transport service for multiple events with short convergence time, low lost rate and high overall bandwidth utilization.

Evolutionary methods for self-organizing cooperation in peer-to-peer networks

The Peer-to-Peer network paradigm is drawing the attention of both final users and researchers for its features. P2P networks shift from the classic client-server approach to a high level of decentralization where there is no central control and all the nodes should be able not only to require services, but to provide them to other peers as well. While on one hand such high level of decentralization might lead to interesting properties like scalability and fault tolerance, on the other hand it implies many new problems to deal with. A key feature of many P2P systems is openness, meaning that everybody is potentially able to join a network with no need for subscription or payment systems. The combination of openness and lack of central control makes it feasible for a user to free-ride, that is to increase its own benefit by using services without allocating resources to satisfy other peers’ requests. One of the main goals when designing a P2P system is therefore to achieve cooperation between users. Given the nature of P2P systems based on simple local interactions of many peers having partial knowledge of the whole system, an interesting way to achieve desired properties on a system scale might consist in obtaining them as emergent properties of the many interactions occurring at local node level. Two methods are typically used to face the problem of cooperation in P2P networks: 1) engineering emergent properties when designing the protocol; 2) study the system as a game and apply Game Theory techniques, especially to find Nash Equilibria in the game and to reach them making the system stable against possible deviant behaviors. In this work we present an evolutionary framework to enforce cooperative behaviour in P2P networks that is alternative to both the methods mentioned above. Our approach is based on an evolutionary algorithm inspired by computational sociology and evolutionary game theory, consisting in having each peer periodically trying to copy another peer which is performing better. The proposed algorithms, called SLAC and SLACER, draw inspiration from tag systems originated in computational sociology, the main idea behind the algorithm consists in having low performance nodes copying high performance ones. The algorithm is run locally by every node and leads to an evolution of the network both from the topology and from the nodes’ strategy point of view. Initial tests with a simple Prisoners’ Dilemma application show how SLAC is able to bring the network to a state of high cooperation independently from the initial network conditions. Interesting results are obtained when studying the effect of cheating nodes on SLAC algorithm. In fact in some cases selfish nodes rationally exploiting the system for their own benefit can actually improve system performance from the cooperation formation point of view. The final step is to apply our results to more realistic scenarios. We put our efforts in studying and improving the BitTorrent protocol. BitTorrent was chosen not only for its popularity but because it has many points in common with SLAC and SLACER algorithms, ranging from the game theoretical inspiration (tit-for-tat-like mechanism) to the swarms topology. We discovered fairness, meant as ratio between uploaded and downloaded data, to be a weakness of the original BitTorrent protocol and we drew inspiration from the knowledge of cooperation formation and maintenance mechanism derived from the development and analysis of SLAC and SLACER, to improve fairness and tackle freeriding and cheating in BitTorrent. We produced an extension of BitTorrent called BitFair that has been evaluated through simulation and has shown the abilities of enforcing fairness and tackling free-riding and cheating nodes.

Criteri di valutazione del protocollo TCP

La diffusione di Internet negli ultimi anni e lo sviluppo sempre crescente nell'ambito delle reti di telecomunicazione, hanno portato oggi ad una vera e propria esplosione della diffusione di nuove tecnologie di trasmissione. Inizialmente il protocollo di trasporto dati, TCP, non era stato pensata per operare in scenari diversi da quello della rete fissa. Con l'introduzione di nuovi scenari, come quello wireless, wimax e satellitare, si è notato come le prestazioni peggiorino in questi ambienti. Proprio per questo, il protocollo TCP ha subito parecchie modifiche negli anni e sono state realizzate alternative atte a migliorare l'inefficienza del protocollo. Le modifiche, a cui il TCP è stato sottoposto, sono basate su alcuni criteri di valutazione e l'introduzione di meccanismi come il controllo del flusso o il controllo di congestione in modo da migliorare le performance in ambienti “ostili”. Molti ricercatori si sono concentrati nello studio e modifica di questi nuovi meccanismi cercando di adattare al meglio il TCP secondo diversi scenari di rete, trascurando così altri criteri un pò meno noti. Dopo aver introdotto lo scenario con la descrizione del protocollo TCP, andremo a descrivere e illustrare questi “nuovi criteri” presentando alcuni recenti studi effettuati, in seguito andremo a presentare un nuova versione del protocollo chiamata Early Warning TCP e nell'ultimo capitolo andremo a presentare delle conclusioni degli studi presentati.

Moduli consensuali nei rapporti tra Stato e autonomie territoriali e ruolo delle Conferenze

Ad oltre un decennio dalla riforma costituzionale del 2001, la non compiuta attuazione della stessa sembra condurre ad una nuova ed assai prossima revisione costituzionale. Nel mutato quadro costituzionale di quest’ultimo periodo l’attenzione e l’interesse sono stati richiamati da una grande quantità di accordi, di intese e di altri moduli consensuali, introdotti ed esitati nei rapporti tra Stato ed autonomie territoriali. Dall’esame del sistema delle Conferenze si è evidenziata la loro indispensabilità ai fini del coordinamento delle azioni politico –amministrative delle autonomie territoriali, ma è anche venuta fuori l’esigenza di ricorrere frequentemente ad altri tipi di moduli consensuali, spesso non tipizzati in ambito legislativo. I principi di sussidiarietà e di leale collaborazione inducono non di rado ad assumere, nella concretezza, forme eterogenee poco chiare e confuse (accordo, intesa, concerto, parere) che, pur considerati i contributi offerti dalla dottrina e dalla giurisprudenza, richiederebbero un intervento da parte del legislatore. L’approfondimento tematico ha rilevato, nel contesto di rapporti tra Stato ed autonomie territoriali, un movimento per così dire ondulatorio tra accese spinte autonomistiche e rimarcate esigenze centralistiche, lasciando ancora nella prospettiva una operativa ed efficiente armonia istituzionale.

Law, Informal Institutions and Trust: an Experimental Perspective

This dissertation has studied how legal and non-legal mechanisms affect the levels of trust and trustworthiness in an economy, and whether and when subtle psychological factors are crucial for establishing trust and even for recovering trust from a breach of contract. The first Chapter has addressed the question of whether formal legal enforcement crowds out or crowds in the amount of trust in a society. We find that formal legal mechanisms, especially formal contracts backed by a powerful authority, normally undermine trust except when they are perceived as legitimate, or when there are no strong social norms of fairness (i.e. the population in a society is considerably heterogeneous), or when the environment in which repeated commercial relationships take place becomes highly uncertain. The second Chapter has examined whether the endogenous adoption of a collective punishment institution can help a society coordinate on an efficient outcome, characterized by high levels of trust and trustworthiness. The experimental results show that the endogenous introduction of collective punishment by means of a majority-voting rule does not significantly improve coordination on the efficient equilibrium. Not all subjects seem to be able to anticipate the change in behavior induced by the introduction of the mechanism, and a majority of them vote against it. The third Chapter has explored whether high-trustors adapt their behavior in response to others’ trustworthiness or untrustworthiness more quickly, which in turn supports them to maintain higher default expectations of others’ trustworthiness relative to low-trustors. Our experimental results reveal that high-trustors are better than low-trustors at predicting others’ trustworthiness because they are less susceptible to the anticipated aversive emotions aroused by the potential betrayal and thereby have a higher willingness to acquire the valuable information about their partner’s actions.

Capuchin Monkeys (Cebus apella) Fail to Be Equitable in an Ultimatum Game

The ultimatum game is a commonly used economics game testing humans' sense of fairness. In the game, a "proposer" is given a sum of money and is told they can split it however they want with another human partner. The partner can then either accept the division and both proposer and responder receive the proposed amounts, or the responder can reject the offer and neither player will get anything. Human subjects from most western cultures typically share almost half of an allotted amount, but it remains unknown whether our close primate relatives share this generosity. Recent attempts to present chimpanzees with the ultimatum game have provided inconclusive results, with some studies finding the animals share humans' disposition to behave 'fairly' and others concluding that chimpanzees act selfishly to maximize their own rewards. Capuchin monkeys are known to share many human and chimpanzee social and cooperative behaviors, and this study was the first to present capuchin monkeys with a version of the ultimatum game. Subjects were presented with two differently colored tokens representing different qualitative reward contingencies, one equitable and the other inequitable in favor of the subject proposer. Subjects could select and place one of the tokens in a transfer container. The capuchins were first tested with a "dictator game" where, after the subject monkey selected a token, the rewards (equitable or inequitable) were distributed to the subject and a nearby partner monkey that was not an active participant. The capuchins were then tested on an ultimatum game in which after the subject selected and placed a token in the container, the container was moved to the partner. The partner needed to remove the token and transfer it back to the experimenter for the rewards to be distributed. As such, the partner could reject the subject's offer by refusing to participate and neither would receive a reward. The experiment was conducted to determine if the subject monkey would select the equitable reward option rather than the selfish option in order to maintain the partner's cooperation in the task. Capuchin subjects behaved selfishly and selected the inequitable token significantly more often than the equitable token in both the dictator and ultimatum game with no significant difference in preference between the two games. Interestingly, despite the occasional occurrence of rejection by the partner monkeys (resulting in no reward for the subject), subjects never altered their strategy, continuing to prefer the selfish token. The study may indicate that capuchin monkeys have an inability to judge the effect of their behavior on a conspecific's reward outcome, or an indifference to the outcome if there is an individual cost associated with behaving prosocially.

Preparing writing centers and tutors for literacy mediation for working class campus-staff

Writing centers work with writers; traditionally services have been focused on undergraduates taking composition classes. More recently, centers have started to attract a wider client base including: students taking labs that require writing; graduate students; and ESL students learning the conventions of U.S. communication. There are very few centers, however, which identify themselves as open to working with all members of the campus-community. Michigan Technological University has one such center. In the Michigan Tech writing center, doors are open to “all students, faculty and staff.” While graduate students, post docs, and professors preparing articles for publication have used the center, for the first time in the collective memory of the center UAW staff members requested center appointments in the summer of 2008. These working class employees were in the process of filling out a work related document, the UAW Position Audit, an approximately seven-page form. This form was their one avenue for requesting a review of the job they were doing; the review was the first step in requesting a raise in job level and pay. This study grew out of the realization that implicit literacy expectations between working class United Auto Workers (UAW) staff and professional class staff were complicating the filling out and filing of the position audit form. Professional class supervisors had designed the form as a measure of fairness, in that each UAW employee on campus was responding to the same set of questions about their work. However, the implicit literacy expectations of supervisors were different from those of many of the employees who were to fill out the form. As a result, questions that were meant to be straightforward to answer were in the eyes of the employees filling out the form, complex. Before coming to the writing center UAW staff had spent months writing out responses to the form; they expressed concerns that their responses still would not meet audience expectations. These writers recognized that they did not yet know exactly what the audience was expecting. The results of this study include a framework for planning writing center sessions that facilitate the acquisition of literacy practices which are new to the user. One important realization from this dissertation is that the social nature of literacy must be kept in the forefront when both planning sessions and when educating tutors to lead these sessions. Literacy scholars such as James Paul Gee, Brian Street, and Shirley Brice Heath are used to show that a person can only know those literacy practices that they have previously acquired. In order to acquire new literacy practices, a person must have social opportunities for hands-on practice and mentoring from someone with experience. The writing center can adapt theory and practices from this dissertation that will facilitate sessions for a range of writers wishing to learn “new” literacy practices. This study also calls for specific changes to writing center tutor education.

Socialism and intrafirm asset allocation

We rely on a survey of Swiss firms to document deviation from first-best for reasons of internal 'fairness' when allicating resources. This 'socialist' practice is more widespread in smaller than in larger firms. It ignores the reputation and past performance of the managers who apply for dunding, but takes into account their hierarchical position and their past use of resources. Socialism is only partially explained by concerns about empire building and managerial optimism, and it is not meant to benefit shareholders.

Gender as a moderator of the fair process effect

This paper examines gender as a moderator of the fair-process effect in an ultimatum game setting. Results from games with 112 German high-school students support the hypothesis that fair procedures can decrease rejection behavior in unfair human allocation decisions. Furthermore, procedural fairness results in a statistically significant difference for women in accepting an unfair distribution. In contrast, procedural fairness appears to have no significant impact on men’s rejection behavior. However, we found no significant gender differences in the perception of procedural fairness. We conclude that, although men perceive procedural fairness similarly to women, this aspect is less important for determining their subsequent behavior. (PsycINFO Database Record (c) 2013 APA, all rights reserved)

Actions speak louder than words

Ethical scandals in business have led to calls for more ethical or moral leadership. Yet, we still know very little about what characterizes ethical leadership and what its positive consequences actually are. We argue that the major question is not about what leaders value, but rather whether their ethical values are regularly reflected in behavioral patterns across situations and situational challenges. To address this, we have begun to build the Ethical Leadership Behavior Scale, which is based on behaviors reflecting concrete manifestations of ethical values (e.g., fairness, respect) across occasions and situational barriers. A study with 592 employees of 110 work units in two departments provided a first test of this scale and demonstrated that the level of ethical leadership behavior predicts important work-related attitudes (job satisfaction, work engagement, affective organizational commitment) and outcomes (health complaints, emotional exhaustion, absenteeism).

Leveraging Trust and Privacy Concerns in Online Social Networks: an Empirical Study

Unprecedented success of Online Social Networks, such as Facebook, has been recently overshadowed by the privacy risks they imply. Weary of privacy concerns and unable to construct their identity in the desired way, users may restrict or even terminate their platform activities. Even though this means a considerable business risk for these platforms, so far there have been no studies on how to enable social network providers to address these problems. This study fills this gap by adopting a fairness perspective to analyze related measures at the disposal of the provider. In a Structural Equation Model with 237 subjects we find that ensuring interactional and procedural justice are two important strategies to support user participation on the platform.

Illegitimate Tasks: Accumulating Evidence for a New Stressor Concept

INTRODUCTION: Task stressors typically refer to characteristics such as not having enough time or resources, ambiguous demands, or the like. We suggest the perceived lack of legitimacy as an additional feature of tasks as a source of stress. Tasks are “illegitimate” to the extent that it is perceived as improper to expect employees to execute them – not because of difficulties in executing them, but because of their content for a given person, time, and situation; they are illegitimate because a) they are not conforming to a specific occupational role, as in “non-nursing activities” (called unreasonable) or b) there is no legitimate need for them to exist (called unnecessary; Semmer et al., 2007). These features make illegitimate tasks a unique task-related stressor. The concept of illegitimate tasks grew from the “Stress-as-Offense-to-Self” theory (SOS; Semmer et al, 2007); it is conceptually related to role stress (Kahn et al., 1964; Beehr & Glazer, 2005) and the organizational justice tradition (Cropanzano et al., 2001; Greenberg, 2010). SOS argues that a threat to one’s self-image is at the core of many stressful experiences. Violating role expectations, illegitimate tasks can be regarded as a special case of role conflict. As roles shape identities, this violation is postulated to constitute a threat to one’s professional identity. Being assigned a task considered illegitimate is likely to be considered unfair. Lack of fairness, in turn, contains a message about one’s social standing, and thus, the self. However, the aspects discussed have not received much attention in the role stress or the justice/fairness tradition. OBJECTIVE: Illegitimate tasks are a rather recent concept that has to be established as a construct in its own right by showing that it is associated with well-being/strain while controlling for other stressors, most notably role conflict and lack of justice. The aim of the presentation is to present the evidence accumulated so far. METHODS AND RESULTS: We present several studies employing different designs, using different control variables, and testing associations with different criteria. Study 1 demonstrates associations of illegitimate tasks with self-esteem, feelings of resentment against one’s organization, and burnout, controlling for distributive justice, role conflict, and social stressors (i.e. tensions). Study 2 yielded comparable results, using the same outcome variables but controlling for distributive as well as procedural / interactional justice. Study 3 demonstrated associations between illegitimate tasks and feelings of stress, sleeping problems, and emotional exhaustion, controlling for demands, control, and social support among medical doctors. Study 4 showed that feeling appreciated by one’s superior acted as a mediator between illegitimate tasks and job satisfaction and resentments towards the military in Swiss military officers. Study 5 demonstrated an association of illegitimate tasks with counterproductive work behavior (Semmer et al. 2010). Studies 1 to 5 were cross-sectional. In Study 6, illegitimate demands predicted irritability and resentments towards one’s organization longitudinally. Study 7 also was longitudinal, focusing on intra-individual variation in multilevel modeling; occasion-specific illegitimate tasks predicted cortisol among those who judged their health as comparatively poor. Studies 1-3 and 6 used SEM, and measurement models that used unreasonable and unnecessary tasks as indicators (isolated parceling) yielded a good fit. IMPLICATIONS & CONCLUSIONS: These studies demonstrate that illegitimate tasks are a stressor in its own right that is worth studying. It illuminates the social meaning of job design, emphasizing the implications of tasks for the (professional) self, and thus combining aspects that are traditionally treated as separate, that is, social aspects and task characteristics. Practical implications are that supervisors and managers should be alerted to the social messages that may be contained in task assignments (cf. Semmer & Beehr, in press).

Hybrid bodies in cyborg sports? The case of Oscar Pistorius

The capabilities of postmodern biotechnology inevitably lead to questioning if it is morally acceptable to use all possibilities offered by technology. In sport, this very complex issue is dealt with by drawing clear boundaries between naturalness and artificiality. Currently, new biotechnology is constantly being produced and with this, boundaries between naturalness and artificiality, between normal and abnormal, human and hybrid are constantly shifting . “Human enhancement” is a fascinating prism that reflects contemporary questions of participation, justice, equality and the autonomy of the subject in all social fields. The area of elite sports is particularly affected by “human enhancement”, according to the principle of exceeding what has come before, of aiming higher, faster and further. This paper analyses the postulated “naturalness” in the regulative and normalising function in the area of elite sports, in connection with Foucault’s theory of governmentality. The example of the South African sprinter Oscar Pistorius appears to be particularly suited to illustrate current definition difficulties in the area of disabled and non-disabled people in differentiated competitive sports. His is a vivid example of a multifaceted body-sociological analysis of current sport culture and the construction of reality or naturalness in the framework of the discourse of drafting and negotiating the accreditation for sprint competitions of non-disabled athletes, most recently in the London Olympics 2012. Using the case study of Oscar Pistorius, the negotiating processes in relation to the argumentation logic, dynamics and resistance in shifting distinctions are presented in detail using the fundamental documents of the IOC, IPC, CAS and IAAF. Represented through the inclusion and exclusion processes are hierarchies of the body that are (re)consolidated and transformed. The central question emerges as to how the worth of equal opportunity and fairness in regard to “naturalness” can be reconsolidated or transformed.