On Secure Transmission over Parallel Relay Eavesdropper Channel

We study a four terminal parallel relay-eavesdropper channel which consists of multiple independent relay-eavesdropper channels as subchannels. For the discrete memoryless case, we establish inner and outer bounds on the rate-equivocation region. For each subchannel, secure transmission is obtained through one of the two coding schemes at the relay: decoding-and-forwarding the source message or confusing the eavesdropper through noise injection. The inner bound allows relay mode selection. For the Gaussian model we establish lower and upper bounds on the perfect secrecy rate. We show that the bounds meet in some special cases, including when the relay does not hear the source. We illustrate the analytical results through some numerical examples.Comment: 8 pages, Presented at the Forty-Eighth Annual Allerton Conference on Communication, Control, and Computing, September 29 - October 1, 2010, Monticello, IL, US

On SDoF of Multi-Receiver Wiretap Channel With Alternating CSIT

We study the problem of secure transmission over a Gaussian multi-input single-output (MISO) two receiver channel with an external eavesdropper, under the assumption that the state of the channel which is available to each receiver is conveyed either perfectly ($P$) or with delay ($D$) to the transmitter. Denoting by $S_1$, $S_2$, and $S_3$ the channel state information at the transmitter (CSIT) of user 1, user 2, and eavesdropper, respectively, the overall CSIT can then alternate between eight possible states, i.e., $(S_1,S_2,S_3) \in \{P,D\}^3$. We denote by $\lambda_{S_1 S_2 S_3}$ the fraction of time during which the state $S_1S_2S_3$ occurs. Under these assumptions, we first consider the Gaussian MISO wiretap channel and characterize the secure degrees of freedom (SDoF). Next, we consider the general multi-receiver setup and characterize the SDoF region of fixed hybrid states $PPD$, $PDP$, and $DDP$. We then focus our attention on the symmetric case in which $\lambda_{PDD}=\lambda_{DPD}$. For this case, we establish bounds on SDoF region. The analysis reveals that alternating CSIT allows synergistic gains in terms of SDoF; and shows that, by opposition to encoding separately over different states, joint encoding across the states enables strictly better secure rates. Furthermore, we specialize our results for the two receivers channel with an external eavesdropper to the two-user broadcast channel. We show that, the synergistic gains in terms of SDoF by alternating CSIT is not restricted to multi-receiver wiretap channels; and, can also be harnessed under broadcast setting.Comment: To Appear in IEEE Transactions on Information Forensics and Securit

Secure Communication over Parallel Relay Channel

We investigate the problem of secure communication over parallel relay channel in the presence of a passive eavesdropper. We consider a four terminal relay-eavesdropper channel which consists of multiple relay-eavesdropper channels as subchannels. For the discrete memoryless model, we establish outer and inner bounds on the rate-equivocation region. The inner bound allows mode selection at the relay. For each subchannel, secure transmission is obtained through one of two coding schemes at the relay: decoding-and-forwarding the source message or confusing the eavesdropper through noise injection. For the Gaussian memoryless channel, we establish lower and upper bounds on the perfect secrecy rate. Furthermore, we study a special case in which the relay does not hear the source and show that under certain conditions the lower and upper bounds coincide. The results established for the parallel Gaussian relay-eavesdropper channel are then applied to study the fading relay-eavesdropper channel. Analytical results are illustrated through some numerical examples.Comment: To Appear in IEEE Transactions on Information Forensics and Securit

Analysis of the Effectiveness of SMS Marketing by Mobile Companies: A Case Study of Telecom Sector in Southern Punjab-Pakistan

The objective of this study is to  explore  indirect effect of factors of SMS advertising i.e. trust, informativeness, and irritation on purchasing behavior through an intervening variable i.e. attitude of the customers. The relationship between these variables were measured through different statistical techniques such as descriptive statistics, correlation, principal component analysis (PCA), and multivariate regression analysis. Primary data was used in this study which was collected through field survey. A questionnaire was constructed through which the views of 319 students of universities belonging to three geographical regions of Pakistan i.e. Bahawalpur, D.G.Khan and Multan Divisions were recorded. Our Results shows positive relationship between trust and informativeness with attitude of the customers, while irritation is negatively related to the attitude of the customers. It may be mentioned that we have taken the attitude of the customers as a positive predictor of purchasing behavior and acts as a mediator. Keywords: Emotional Intelligence, Personality Traits, Transformational Leadership, Leader’s Effectivenes

Secure Degrees of Freedom of MIMO X-Channels with Output Feedback and Delayed CSIT

We investigate the problem of secure transmission over a two-user multi-input multi-output (MIMO) X-channel in which channel state information is provided with one-unit delay to both transmitters (CSIT), and each receiver feeds back its channel output to a different transmitter. We refer to this model as MIMO X-channel with asymmetric output feedback and delayed CSIT. The transmitters are equipped with M-antennas each, and the receivers are equipped with N-antennas each. For this model, accounting for both messages at each receiver, we characterize the optimal sum secure degrees of freedom (SDoF) region. We show that, in presence of asymmetric output feedback and delayed CSIT, the sum SDoF region of the MIMO X-channel is same as the SDoF region of a two-user MIMO BC with 2M-antennas at the transmitter, N-antennas at each receiver and delayed CSIT. This result shows that, upon availability of asymmetric output feedback and delayed CSIT, there is no performance loss in terms of sum SDoF due to the distributed nature of the transmitters. Next, we show that this result also holds if only output feedback is conveyed to the transmitters, but in a symmetric manner, i.e., each receiver feeds back its output to both transmitters and no CSIT. We also study the case in which only asymmetric output feedback is provided to the transmitters, i.e., without CSIT, and derive a lower bound on the sum SDoF for this model. Furthermore, we specialize our results to the case in which there are no security constraints. In particular, similar to the setting with security constraints, we show that the optimal sum DoF region of the (M,M,N,N)--MIMO X-channel with asymmetric output feedback and delayed CSIT is same as the DoF region of a two-user MIMO BC with 2M-antennas at the transmitter, N-antennas at each receiver, and delayed CSIT. We illustrate our results with some numerical examples.Comment: To Appear in IEEE Transactions on Information Forensics and Securit

Software Engineering: Factors Affect on Requirement Prioritization

Software engineering research is yet in its early stages hence it needs evaluation. So, software engineers think about experimental research and try to adopt analytical approaches to validate results like in other sciences. It should be asserting that requirement engineering process is to use requirements prioritization. The use of requirements prioritization helps the anatomy of requirements and isolates the most important requirements. A lot of prioritization techniques, practices and methodologies are used in software requirements. But lack of empirical search program and proficient methodology, was not decide which should be implemented. In this research, the requirement prioritization for systematical reviews was carried out. Based on systematic review, a framework is introduced for further research within requirement prioritization. This paper described a framework for scrutinize the discussion that take place during requirements elicitation and requirements prioritization. The survey presented in the paper gives a practical view how to prioritize the requirements. It also reflects the requirements prioritization in the industries needs. Which factors of the requirements engineering affect the requirements prioritization

Making Every Contact Count: Improving the Physical Health of People with Mental Health Problems

The physical health of people with mental health problems is a significant source of health inequality, with this group three times more likely to have a physical illness and dying 15-20 years earlier than counterparts without recognised mental health problems. Making Every Contact Count (MECC) is an opportunistic health promotion strategy supporting people to make healthier choices and achieve positive long-term lifestyle changes. The purpose of this study was to explore the barriers and facilitators of the MECC approach to improving the physical health of people with mental health problems in primary care. Ten people with mental health problems and ten GPs including stakeholders within the Clinical Commissioning Group were interviewed. Thematic analysis identified themes relating to patient factors, clinician communication, and systemic factors. These were further analysed based on principles of realist evaluation, articulating ‘context-mechanism-outcome’ (CMO) statements; whereby, in a specified context a particular mechanism generates different outcomes. Patients were more likely to take on brief interventions if they trusted and had good rapport with their clinician. Clinicians valued transmitting knowledge of the effects of the unhealthy lifestyles and how to address these. Systemic factors included continuity of care and the annual review, although a number of patients viewed this as lacking fruitful discussion. Medication reviews were highlighted as an area for improvement. Taken together, these patient, clinician and systemic factors can be used to ‘make every contact count’ in improving the physical health of people with mental health problems. There are also gaps in terms of clinician skills as well as processes that can be improved to ‘making every contact count.