A key distribution scheme for mobile underwater wireless sensor networks

Wireless Sensor Networks consist of small battery-limited devices called sensor nodes. They are used for collecting data from surrounding environment and relay them via wireless communication. One of the recent application areas is underwater sensing. Communication in Underwater Wireless Sensor Networks (UWSN) is different from airborne communication. Radio frequencies cannot be used for UWSN. Instead acoustic waves, which cause extra challenges, are used in UWSN. When UWSNs are deployed in hostile environment, nodes can be captured by an adversary. In order to secure UWSNs, firstly key distribution problem must be addressed. Moreover, UWSNs are inherently mobile since the nodes may be drifted in the sea. In this thesis, we propose a key distribution model which is applied for two group mobility models, namely (i) nomadic mobility model and (ii) meandering current mobility model. Our nomadic mobility based key distribution scheme works in three dimensions. However, this scheme is suitable only for small coastal areas. On the other hand, our meandering mobility based key distribution model is a two dimensional one and spans several kilometers in the open sea. In both schemes, a hierarchical structure is used. Secure and resilient group communication is handled via well-known Blom's key distribution scheme. We analyzed the performance of the proposed schemes using simulations. Our results show that secure connectivity of both schemes is generally high. Of course, mobility causes some temporary decreases in the connectivity, but our schemes help to heal the connectivity performance in time. Moreover, our schemes show good resiliency performance such that capture of some nodes by an adversary only causes very small amount of links between uncaptured nodes to be compromised

A highly resilient and zone-based key predistribution protocol for multiphase wireless sensor networks

Pairwise key distribution among the sensor nodes is an essential problem for providing security in Wireless Sensor Networks (WSNs). The common approach for this problem is random key predistribution, which suffers from resiliency issues in case of node captures by adversaries. In the literature, the resiliency problem is addressed by zone-based deployment models that use prior deployment knowledge. Another remedy in the literature, which is for multiphase WSNs, aims to provide self-healing property via periodic deployments of sensor nodes with fresh keys over the sensor field. However, to the best of our knowledge, these two approaches have never been combined before in the literature. In this paper, we propose a zone-based key predistribution approach for multiphase WSNs. Our approach combines the best parts of these approaches and provides self-healing property with up to 9-fold more resiliency as compared to an existing scheme. Moreover, our scheme ensures almost 100% secure connectivity, which means a sensor node shares at least one key with almost all of its neighbors

Privacy in Mobile Computing for Location-Sharing-Based Services

Location-Sharing-Based Services (LSBS) complement Location-Based Services by using locations from a group of users, and not just individuals, to provide some contextualized service based on the locations in the group. However, there are growing concerns about the misuse of location data by third-parties, which fuels the need for more privacy controls in such services. We address the relevant problem of privacy in LSBSs by providing practical and effective solutions to the privacy problem in one such service, namely the fair rendez-vous point (FRVP) determination service. The privacy preserving FRVP (PPFRVP) problem is general enough and nicely captures the computations and privacy requirements in LSBSs. In this paper, we propose two privacy-preserving algorithms for the FRVP problem and analytically evaluate their privacy in both passive and active adversarial scenarios. We study the practical feasibility and performance of the proposed approaches by implementing them on Nokia mobile devices. By means of a targeted user-study, we attempt to gain further understanding of the popularity, the privacy and acceptance of the proposed solutions

"Once Upon a Place": Compute Your Meeting Location Privately

Popular services such as Doodle Mobile and Tymelie are extremely useful planning tools that enable mobile-phone users to determine common meeting time(s) for events. Similar planning tools for determining optimal meeting locations, based on the location preferences of the users, are highly desirable for event planning and management in popular mobile phone applications, such as taxi sharing, route planning and mobile participatory sensing. Yet, they have received very little attention by researchers. An important, and often overlooked, facet of such planning applications is the privacy of the participating users and their preferences; users want to agree on a meeting location without necessarily revealing their location preferences to the service provider or to the other users. In this paper, we address the problem of privacy-preserving optimal meeting-location computation, especially focusing on its applicability to current mobile devices and applications. We first define the notion of privacy in such computations. Second, we model the problem of optimal meeting-location computation as a privacy-preserving k-center problem and we design two solutions; both solutions take advantage of the homomorphic properties of well-known cryptosystems by Boneh-Goh-Nissim, ElGamal and Paillier in order to perform oblivious computations. Third, we implement the proposed solutions on a testbed of the latest generation Nokia mobile devices and study their performance. Finally, we assess the utility and expectations, in terms of privacy and usability, of the proposed solutions by means of a targeted survey and user-study of mobile-phone users

Hepatoprotective actions of melatonin by mainly modulating oxidative status and apoptosis rate in lipopolysaccharide-induced liver damage

Aim: One of the serious complications of sepsis is liver damage and liver failure. This study aimed to evaluate the protective and therapeutic potential of melatonin in rats with lipopolysaccharide-induced sepsis. Main methods: Female Spraque–Dawley rats received single a dose of 7.5 mg/kg lipopolysaccharide in saline to create a 24-h sepsis model. One of the other groups received melatonin at a dose of 10 mg/kg/day beginning 1 week before sepsis induction to the end of the experiment. The melatonin group received the same doses of melatonin for the same duration but not lipopolysaccharide. The vehicle group received the same doses of saline, the vehicle of melatonin, for the same duration. Twenty-four hours after the last injection, the rats were decapitated. By appropriate histochemical, immunohistochemical, biochemical, and molecular techniques, anti-necrotic, anti-apoptotic, anti-necroptotic, anti-inflammatory, and antioxidant effects of melatonin were assessed. Key findings: Lipopolysaccharide has disrupted liver functions by inducing oxidative stress, inflammation, necrotic, apoptotic, and necroptotic cell death, thus disrupting liver functions. Melatonin was found to be beneficial in terms of inhibiting the intrinsic pathway of apoptosis and tissue oxidant levels, stimulating tissue antioxidant enzyme levels, and restoring hepatocyte functions. Significance: Melatonin, at those doses and duration, was found to be hepatoprotective by mainly modulating oxidative status and apoptosis rate, however, failed to significantly reduce histopathological damage. We suggest that longer-term melatonin administration may produce anti-inflammatory and anti-necrotic effects as well. © 2023 Informa UK Limited, trading as Taylor & Francis Group

The predictive role of perceived the psychological and behavioral control of the parent and internal-external locus of control in anger expression

Bu araştırmada anneden algılanan psikolojik ve davranışsal kontrolün ve bireyin denetim odağının öfkenin ifade tarzları üzerindeki etkisi incelenmiştir. Buna göre, öfke duygusunun ortaya çıkışında olayları ve kişileri algılama biçiminin önemini gösteren denetim odağı; çocukluk döneminde anneden algılanan psikolojik-davranışsal kontrol ve çocukluk dönemi hiperaktivite, dürtüsellik ve dikkat dağınıklığı değerlendirmeye alınmıştır. Bu kapsamda araştırmaya 18-28 yaş aralığında toplam 405 üniversite öğrencisi katılmıştır. Katılımcılar Demografik Bilgi Formu, Algılanan Ebeveyn Psikolojik Kontrolü Ölçeği, Algılanan Ebeveyn Davranışsal Kontrolü Ölçeği, Rotter Denetim Odağı Ölçeği, Wender Utah Derecelendirme Ölçeği ve Sürekli Öfke ve Öfke ifade Tarz Ölçeği'ni tamamlamışlardır. Katılımcılarda grup etkisinin ve cinsiyet farklılıklarının belirgin olarak ortaya çıktığı araştırmada, sürekli öfke düzeyleri ve ifade tarzlarını yordamak amacıyla biyo-psiko-sosyal yaklaşım kapsamında bir model oluşturularak analiz yapılmıştır. Buna göre hem kadın hem de erkek katılımcılarda sürekli öfke düzeyleri ve ifade tarzlarının farklılaştığı; çocukluk dönemi yaşantılarına yönelik algının da bugünkü öfke yaşantısını yordadığı görülmektedir. Bu kapsamda en kritik faktör de katılımcıların çocukluk dönemine yönelik belirttikleri hiperaktivite, dürtüsellik ve dikkat dağınıklığı düzeyi olarak bulunmuştur. Sonuçlar hem öfke ifadesinde ebeveyn psikolojik-davranışsal kontrolü ve denetim odağının yordayıcı rolü açısından hem de uygulamaya katkıları açısından tartışılmıştır.In this research, it was aimed to investigate the perceived psychological and behavioral control of the mother and the influence of the individual's locus of control on the expression styles of the anger. Accordingly, in the emergence of anger, the locus of control, which shows the importance of the way how events and other people are perceived; psychological-behavioral control perceived from the mother during childhood and childhood hyperactivity, impulsivity and distractibility were evaluated. Within this scope, a total of 405 university students participated in the study between the ages of 18-28. Participants completed the Demographic Information Form, Perceived Parental Psychological Control Scale, Perceived Parental Behavioral Control Scale, Rotter's Internal-External Locus of Control Scale, Wender Utah Rating Scale, and Trait Anger and Anger Expression Scale. In the study of the group effect and gender differences in the participants, a model within the bio-psycho-social approach was developed to predict the levels of State anger and expression styles. According to this, in both male and female participants, state anger levels and expression styles differed; it seems that the childhood experiences are predicting the current anger experience. In this context, the most critical factor was the level of hyperactivity, impulsivity and distractibility that participants indicated for childhood. The results have been discussed both in terms of their predictive role of parental psychological-behavioral control and locus of control in anger expression, as well as their contribution to literature and implications of the study were presented