Malicious node traceback in opportunistic networks using merkle trees

Security is a major challenge in Opportunistic Networks because of its characteristics, such as open medium, dynamic topology, no centralized management and absent clear lines of defense. A packet dropping attack is one of the major security threats in OppNets since neither source nodes nor destination nodes have the knowledge of where or when the packet will be dropped. In this paper, we present a malicious nodes detection mechanism against a special type of packet dropping attack where the malicious node drops one or more packets and then injects new fake packets instead. Our novel detection and traceback mechanism is very powerful and has very high accuracy. Each node can detect and then traceback the malicious nodes based on a solid and powerful idea that is, Merkle tree hashing technique. In our defense techniques we have two stages. The first stage is to detect the attack, and the second stage is to find the malicious nodes. We have compared our approach with the acknowledgement based mechanisms and the networks coding based mechanism which are well known approaches in the literature. Simulation results show this robust mechanism achieves a very high accuracy and detection rate.

Defense and traceback mechanisms in opportunistic wireless networks

 In this thesis, we have identified a novel attack in OppNets, a special type of packet dropping attack where the malicious node(s) drops one or more packets (not all the packets) and then injects new fake packets instead. We name this novel attack as the Catabolism attack and propose a novel attack detection and traceback approach against this attack referred to as the Anabolism defence. As part of the Anabolism defence approach we have proposed three techniques: time-based, Merkle tree based and Hash chain based techniques for attack detection and malicious node(s) traceback. We provide mathematical models that show our novel detection and traceback mechanisms to be very effective and detailed simulation results show our defence mechanisms to achieve a very high accuracy and detection rate.

Malicious node detection in OppNets using hash chain technique

Opportunistic Networks aim to set a reliable networks where the nodes has no end-To-end connection and the communication links often suffer from frequent disruption and long delays. The design of the OppNets routing protocols is facing a serious challenges such as the protection of the data confidentiality and integrity. OppNets exploit the characteristics of the human social, such as similarities, daily routines, mobility patterns and interests to perform the message routing and data sharing. Packet dropping attack is one of the hardest attacks in Opportunistic Networks as both the source nodes and the destination nodes have no knowledge of where or when the packet will be dropped. In this paper, we present a new malicious nodes detection technique against packet faking attack where the malicious node drops one or more packets and instead of them injects new fake packets. We have called this novel attack in our previous works a packet faking attack. Each node in Opportunistic Networks can detect and then traceback the malicious nodes based on a solid and powerful idea that is, hash chain techniques. In our hash chain based defense techniques we have two phases. The first phases is to detect the attack, and the second phases is to find the malicious nodes. We have compared our approach with the acknowledgement based mechanisms and the networks coding based mechanism which are well known approaches in the literature. In our simulation, we have achieved a very high node detection accuracy and low false negative rate.

Intercultural service encounters : an exploratory study of customer experiences

Intercultural contact occurs on a daily basis across all facets of life, and is reflective of Australia’s multicultural society. This trend is observed in many Western industrialised nations and has contributed to a growing body of research and literature in the field of managing cultural diversity. While much of this research is focused on the internal context of the workplace, relatively little attention has been given to the impact of culture on the service provider and customer interface. In an effort to shed some light on the service experiences of culturally diverse customers, a series of exploratory interviews were conducted. The findings suggest that on the basis of service provider behaviors (both verbal and nonverbal), culturally diverse customers perceive they are the recipients of inequitable service and consequently experience low levels of satisfaction.

Conceptualizing the ιnfluence of the self-service technology context on consumer voice

The self-service technology (SST) context is characterized by consumer participation in service production and delivery, independent of service personnel; a lack of interpersonal interaction between consumers and service personnel; and consumers being required tointerface and interact with technology. With these features of the SST context in mind, in situations where SSTs fail to perform as promised, some challenges arise: consumers who are dissatisfied do not have the security or reassurance of service personnel to assist them; service personnel do not have the opportunity to prompt consumers to voice their dissatisfaction; and consumers need to initiate their own complaint response. If consumers fail to report their dissatisfaction directly to the organization, organizations will not know that a problem exists and may experience negative consequences such as consumer switching behavior. As reports of consumer dissatisfaction with SSTs become increasingly common, it is important, therefore, to investigate how organizations with SST-based offerings can encourage consumers to voice their dissatisfaction directly to the organization. Although the antecedents of consumer voice are well documented in the interpersonal services context, in the context of SSTs they have been subject to very little conceptual or empirical scrutiny. This paper argues that voice needs to be revisited with respect to SSTs due to their unique characteristics compared to interpersonal services, and presents a conceptual model of the antecedents of consumers' voice behavior in the context of SSTs.

An exploration of relational customers` response to service failure

Purpose – The purpose of this paper is to examine how customers with different relational bonds respond to the same service failure. In particular, the framework to service failure and recovery devised by Fournier and Mick is applied.
Design/methodology/approach – To uncover rich emotional and cognitive responses to service failure, in-depth interviews with eight former and current patrons of an Australian opera were used.
Findings – Three types of relationship were identified: satisfaction-as-love (SaL), satisfaction-as-trust (SaT) and satisfaction-as-control (SaC). Each responded to the same failure in different ways. SaL customers had emotional bonds with the product category and thus reaffiremed their loyalty following the failure. SaT customers saw the service failure and inadequate recovery as a breach of the brand's implied promise and thus excited the relationship. SaC customers took charge of the situation, using their status to improve their situation and then defended the brand.
Practical implications – The findings indicate the importance of customizing service recovery strategies, in this case to those customers with the strongest emotional bonds to the brand, not the product class.
Originality/value – This is the first paper to examine how relational customers respond to service failure and identify how different customer-brand relationships result in different post-failure reactions and expectations of service recovery.

Enabling successful web-based information technology support for enterprise customers: a service provider perspective of stakeholder-based issues

An understanding by support organisations of the key factors enabling successful enterprise after-sales customer support provision when using Web-based Selfservice Systems (WSSs) is essential to making  improvements in such systems. This paper reports key stakeholder-oriented findings from an interpretive study of critical success factors (CSFs) for the transfer of after-sales support-oriented knowledge from an information technology (IT) service provider to enterprise customers when a WSS is used. The findings suggest that researchers and practitioners should consider WSSs within a complex network of service providers, business partners and customer firms. The paper also clearly points to a need for support organisations to engage in greater collaboration and integration of WSSs with enterprise customers and business partners.

Exploring the role of relationship variables in predicting customer voice to a service worker

Customers’ perceptions of service workers’ trustworthiness and power, and their commitment to the service worker were investigated as possible determinants of the likelihood of customer voice directly to the service worker in the event of a service failure. Set in the context of hairdressing salons, it was found that hair stylists’ perceived trust (benevolence and credibility) and expert power were positively associated with clients’ intention to voice. By contrast, the level of coercive power hair stylists were perceived to have was negatively associated with intentions to voice. Hair stylists’ perceived benevolence was the strongest predictor of client voice.

A construct of sequential service quality in service encounter chains

Studies of the construct of service quality have traditionally been undertaken from the perspective of the service receiver. More recently, research has focused on both the service provider's perspective and the service receiver's perspective. In addition, there have also been some triadic network approaches to the study of service quality. However, there has been very little research into sequential service quality in service-encounter chains (that is, consecutive service performances in a series of service encounters). The incorporation of connected service encounters in services management can improve understanding of sequential service quality in service-encounter chains. This paper provides a customized construct of sequential service quality and  highlights the importance of time, context, and performance threshold in service-encounter chains. Furthermore, the paper presents a customized six-dimensional construct of sequential service quality.

Heterogeneity in service delivery and inequity in access are common characteristics of chronic heart failure management programs

Background: The prevalence of heart failure in Australia is similar to that of Europe. In Australia, chronic heart failure management programs (CHF-MPs) have become part of standard care for patients with Chronic Heart Failure (CHF). However, heterogeneity among programs is common which can result in variable patient outcomes.

Method: A national survey was undertaken of 59 post-discharge CHF-MPs identified from within the Australian health care system. Two had ceased operating and one centre declined to participate in the study. A 33-item investigator-developed questionnaire, examining the characteristics and interventions used within each CHF-MP, was sent to the remaining 56 CHF-MPs. A response rate of 100% was achieved.

Results: Our survey revealed a disproportional distribution of CHF-MPs across the Australian continent: the State of Victoria had 3.6 CHF-MPs/million population, New South Wales had 3.7 CHF-MPs/million population, Queensland had 1 program/million population, South Australia had 0.3 CHF-MPs/million population and Western Australia had 1 program/million population.Overall, 8000 postdischarge CHF pts (median: 126; IQR: 26-260) were managed via CHF-MPs. Approximately 40,000 CHF pts are discharged from metropolitan institutions nationally, this represents only 22% of the potential caseload for these cost-effective CHF-MPs. Only 8% of these programs were located within rural regions. The majority of CHF-MPs were located within an acute metropolitan hospital (52%) and 36% were community based (all associated with a hospital). Heterogeneity of CHF-MPs in applied models of care was evident with 75% of CHF-MPs offering CHF outpatient clinics and 77% conducting home visits. Of the programs offering home visits 78% were funded by regional government (p<0.048). There were no nurse-led CHF outpatient clinics. A hybrid approach to CHF-MPs was common with many CHF-MPs comprising an outpatient clinic, home visits and inpatient visits. Various medications were titrated by nurses in 43% of CHF-MPs. In the programs that allowed nurses to titrate medications 79% were located in an acute hospital (p<0.011).

Conclusion: Variability of service availability is of concern within the context of universal coverage. In addition, heterogeneity between programs and the diversity in models of care delivery highlights the inconsistency and questions the quality of health related outcomes. We are currently analysing health outcome data from the 1015 patients managed in these CHF-MPs to describe the relationship between quality of care and health outcomes.

Role of organizational service recovery actions on sustomer switching intentions in a process based service failure : does speed of recovery matters?

The study examines how organizational activities of compensation and empowerment impact on consumers switching intentions and also whether these differ based on the speed of service recovery. Data is collected using hypothetical scenarios in a situation of process failure. It is found that there is no direct effect of either compensation or empowerment on switching intent, although the interaction effect is significant when recovery occurs quickly.

Web-based self-service systems for managed IT support: service provider perspectives of stakeholder-based issues

This chapter explores the provision of after-sales information technology (IT) support services using Web-based self-service systems (WSSs) in a business-to-business (B2B) context. A recent study conducted at six large multi-national IT support organisations revealed a number of critical success factors (CSFs) and stakeholder-based issues. To better identify and understand these important enablers and barriers, we explain how WSSs should be considered within a complex network of service providers, business partners and customer firms. The CSFs and stakeholder-based issues are discussed. The chapter highlights that for more successful service provision using WSSs, IT service providers should collaborate more effectively with enterprise customers and business partners and should better integrate their WSSs.

Interoperable and transparent dynamic deployment of web services for service oriented grids

Dynamic deployment of Web services is a term used frequently when describing the selection and deployment of a service to a grid host. Although current grid systems (such as Globus) provide dynamic deployment, the requirements of the service being deployed are not considered. Therefore truly dynamic deployment cannot be achieved as the services deployed are restricted to the grid system used. We present a dynamic deployment mechanism as part of self configuration in a service oriented grid environment. The dynamic deployment mechanism takes the requirements of the service into consideration, including parameters such as the operating system required to execute the service, the required software libraries, any additional required software packages, price and Quality of Service (QoS) parameters.

Conceptualising the effect of self-service technologies on established brands

Self-service technologies (SSTs), such as machine assisted and electronic services are prevalent. Many established brands in industries such as banking, retailing, and hospitality have adopted SSTs to complement or replace existing channels of service delivery, e.g., face-to-face service. However, the influence of SSTs on established brands has not been examined previously. In the light of this, a conceptual model is proposed that incorporates SST-related variables and their influence on brand satisfaction, brand associations, brand attitudes, and brand loyalty, along with customers' future likelihood to reuse the SST. Arguably, these outcomes affect brand equity and the long-term survival of SSTs.

The influence of guarantee compensation and fix on service recovery

This study employed a 3 x 2 full-factorial, between-subjects design experiment examining the influence of service guarantee compensation and fix on hotel guests’ satisfaction following invocation of a service guarantee. The study involved a sample of 390 online panel members. As expected, satisfaction is enhanced when the problem is corrected, however overcompensating guests beyond what was initially promised does not enhance satisfaction evaluations. Increasing compensation from the low to the medium (promised) level results in stronger satisfaction ratings when the problem is fixed versus when it is not.