Proactive Caching for Energy-Efficiency in Wireless Networks: A Markov Decision Process Approach

Content caching in wireless networks provides a substantial opportunity to trade off low cost memory storage with energy consumption, yet finding the optimal causal policy with low computational complexity remains a challenge. This paper models the Joint Pushing and Caching (JPC) problem as a Markov Decision Process (MDP) and provides a solution to determine the optimal randomized policy. A novel approach to decouple the influence from buffer occupancy and user requests is proposed to turn the high-dimensional optimization problem into three low-dimensional ones. Furthermore, a non-iterative algorithm to solve one of the sub-problems is presented, exploiting a structural property we found as \textit{generalized monotonicity}, and hence significantly reduces the computational complexity. The result attains close performance in comparison with theoretical bounds from non-practical policies, while benefiting from higher time efficiency than the unadapted MDP solution.Comment: 6 pages, 6 figures, submitted to IEEE International Conference on Communications 201

Energy Aware Transmission in Cellular Uplink with Clustered Base Station Cooperation

We provide an analytical formula to evaluate the performance of the uplink of planar cellular networks when joint processing is enabled among limited number of base stations in a generalised fading environment. Focusing on user transmission power allocation techniques to mitigate inter-cluster interference we investigate the system's spectral-energy efficiency trade-off. The paper addresses the gains in both cell throughput and transmissions energy efficiency due to the combined strategies of base station cooperation and user power management. We assess the effect of the propagation environment and of the key network design parameters of cooperation cluster size and inter-site distance on the overall performance providing numerical results for a real-world scenario

Integrated circuit reliability testing

A technique is described for use in determining the reliability of microscopic conductors deposited on an uneven surface of an integrated circuit device. A wafer containing integrated circuit chips is formed with a test area having regions of different heights. At the time the conductors are formed on the chip areas of the wafer, an elongated serpentine assay conductor is deposited on the test area so the assay conductor extends over multiple steps between regions of different heights. Also, a first test conductor is deposited in the test area upon a uniform region of first height, and a second test conductor is deposited in the test area upon a uniform region of second height. The occurrence of high resistances at the steps between regions of different height is indicated by deriving the measured length of the serpentine conductor using the resistance measured between the ends of the serpentine conductor, and comparing that to the design length of the serpentine conductor. The percentage by which the measured length exceeds the design length, at which the integrated circuit will be discarded, depends on the required reliability of the integrated circuit

H2-ARQ-relaying: spectrum and energy efficiency perspectives

In this paper, we propose novel Hybrid Automatic Repeat re-Quest (HARQ) strategies used in conjunction with hybrid relaying schemes, named as H2-ARQ-Relaying. The strategies allow the relay to dynamically switch between amplify-and-forward/compress-and-forward and decode-and-forward schemes according to its decoding status. The performance analysis is conducted from both the spectrum and energy efficiency perspectives. The spectrum efficiency of the proposed strategies, in terms of the maximum throughput, is significantly improved compared with their non-hybrid counterparts under the same constraints. The consumed energy per bit is optimized by manipulating the node activation time, the transmission energy and the power allocation between the source and the relay. The circuitry energy consumption of all involved nodes is taken into consideration. Numerical results shed light on how and when the energy efficiency can be improved in cooperative HARQ. For instance, cooperative HARQ is shown to be energy efficient in long distance transmission only. Furthermore, we consider the fact that the compress-and-forward scheme requires instantaneous signal to noise ratios of all three constituent links. However, this requirement can be impractical in some cases. In this regard, we introduce an improved strategy where only partial and affordable channel state information feedback is needed

Average Energy Efficiency Contours for Single Carrier AWGN MAC

Energy efficiency has become increasingly important in wireless communications, with significant environmental and financial benefits. This paper studies the achievable capacity region of a single carrier uplink channel consisting of two transmitters and a single receiver, and uses average energy efficiency contours to find the optimal rate pair based on four different targets: Maximum energy efficiency, a trade-off between maximum energy efficiency and rate fairness, achieving energy efficiency target with maximum sum-rate and achieving energy efficiency target with fairness. In addition to the transmit power, circuit power is also accounted for, with the maximum transmit power constrained to a fixed value. Simulation results demonstrate the achievability of the optimal energy-efficient rate pair within the capacity region, and provide the trade-off for energy efficiency, fairness and maximum sum-rate

The Beneficial Techniques in Preprocessing Step of Skin Cancer Detection System Comparing

AbstractAutomatic diagnostics of skin cancer is one of the most challenging problems in medical image processing. It helps physicians to decide whether a skin melanoma is benign or malignant. So, determining the more efficient methods of detection to reduce the rate of errors is a vital issue among researchers. Preprocessing is the first stage of detection to improve the quality of images, removing the irrelevant noises and unwanted parts in the background of the skin images. The purpose of this paper is to gather the preprocessing approaches can be used in skin cancer images. This paper provides good starting for researchers in their automatic skin cancer detections

Automatic skin cancer detection system

University of Technology Sydney. Faculty of Engineering and Information Technology.During recent decades, the incident of malignant melanoma as the lethal form of skin cancer has been raised. The occurrence in Australia is much higher than US, UK, and Canada with the cases more than 10,000 diagnosis and annual mortality of 1250 people. The persistent raise of this cancer in the worldwide, the high medical cost and death rate have prioritized the early diagnosis of this cancer. The anticipation and cure of melanoma is strictly relevant to its thickness, if it can be detected early, the survival rate would be increased. Although lots of effort has been made to advance the detection of skin cancers, the challenging concerns still about it. The computer-based detection systems can improve the diagnosis rate of melanoma by 5–30% in comparison with the naked-eye. Since the visual perception often involve some faults, the necessity of second opinion with higher accuracy and reliability is highlighted. On the other hand, it reduces the task and responsibilities that are performed by physicians. Many researches have been developed in automated detection of melanoma. The potential advantages of such studies are significant and incalculable. Moreover, the difficulties entangle are a lot, and the new contributions in the area are highly appreciated. However, it is extensively acknowledged that the more trustful and reliable detection systems require higher accuracy. The purpose of this thesis is to propose an algorithm for skin cancer diagnosis that is able to classify lesions as malignant or benign automatically. The different components in an automated diagnosis of skin cancer includes: Pre-processing, segmentation, feature extraction and selection, and classification. In this thesis, after selecting the best image enhancement techniques which are achieved by applying and comparing different noise removal and contrast enhancement techniques on images, the segmentation stage is performed. In this stage, a fully automated segmentation algorithm in dermoscopy images based on k-mean and level-set algorithms are proposed and compared with other algorithms mentioned in this thesis using statistical tools. Proposed algorithm shows the improvement in the results. In the next stage, after extracting the various features of images, a fully automated feature selection algorithm, Smart PSO-SVM, which optimizes the feature selection stage, is proposed. Comparative study of proposed algorithm with other algorithms is performed to analyse the performance of proposed algorithm among others. The results obtained in the best subset of features which feed the classification stage. In classification stage, the use of SA-SVM as a new classifier in the area of skin cancer detection systems is proposed. The average accuracy and F-score are estimated as 87.0611% and 0.9167 respectively. The statistical evaluation using t-test also shows the superiority of proposed algorithm when compares with other algorithms in this thesis

Frequency planning for clustered jointly processed cellular multiple access channel

Owing to limited resources, it is hard to guarantee minimum service levels to all users in conventional cellular systems. Although global cooperation of access points (APs) is considered promising, practical means of enhancing efficiency of cellular systems is by considering distributed or clustered jointly processed APs. The authors present a novel `quality of service (QoS) balancing scheme' to maximise sum rate as well as achieve cell-based fairness for clustered jointly processed cellular multiple access channel (referred to as CC-CMAC). Closed-form cell level QoS balancing function is derived. Maximisation of this function is proved as an NP hard problem. Hence, using power-frequency granularity, a modified genetic algorithm (GA) is proposed. For inter site distance (ISD) <; 500 m, results show that with no fairness considered, the upper bound of the capacity region is achievable. Applying hard fairness restraints on users transmitting in moderately dense AP system, 20% reduction in sum rate contribution increases fairness by upto 10%. The flexible QoS can be applied on a GA-based centralised dynamic frequency planner architecture

Information theoretic analysis of LSD scheme

In this paper, the capacity region of Low Density Signature Multiple Access Channel (LDS-MAC) is calculated through information theoretic analysis. LDS Code Division Multiple Access (LDS-CDMA) uses spreading sequences of low density for spreading the data symbols in time domain. This technique benefits from a less complex Multiuser Detector (MUD) compared to conventional CDMA with optimum MUD; while keeping the performance close to the single user scenario for up to 200% loaded conditions. Also evaluated is the effect of different factors on the capacity of LDS MAC

A Psychoanalytic Feminist Reading of Ten Novels by Naguib Mahfouz Baharak

In this research, psychoanalytic feminists' contestations based on Sigmund Freud's and Jacques Lacan's theories will be underlined. The postulations of the psychoanalytic feminists will form three main themes of this research. These three themes are Women Defying the Patriarchy and The Patriarchy Regulating Women and The Manifestation of the Regulation of Women. These themes will help us illuminate the notion of women's threatening presence in Mahfouz's novels and the patriarchy's resisting the danger. Women's power to destabilise the structures of the patriarchal society will be expounded by referring to Luce Irigaray, Julia Kristeva, Judith Butler, Helen Cixous and Jessica Benjamin's hypotheses. It will be mentioned that through their connection to death, the reproductive ability, their jouissance, women are able to threaten the symbolic law. They even try to reach their intersubjectivity and become a woman which the symbolic world attempts to hinder. They can also make men dependent on them and make them feel impotent. Facing women's vigour, patriarchy's fear will also be highlighted and it will be explained that it endeavours to suppress women by assuming different roles for them such as satisfiers, virgin and whore figures, derelict and sacrificed. The symbolic world even tries to turn women to objects of exchange and desire, silence them and change them to phallic beings. This thesis will present the extend that Mahfouz's female characters can endanger the stability of the patriarchal world of his novel and how his male characters attempt to counter his women. In this research, men's objectification and controlling women through gaze will be elaborated and it will be mentioned that in order to resist men's voyeuristic pleasure veiling is advocated and the critics' ideas supporting and rejecting it will be discussed in general and in Egypt. Patriarchay's attaching value to virgins and girls deflowered outside marriage being devalued will also be discussed. The notion of prostitution will also be highlighted in order to show that women might go astray in their pursuit of independence and individuality. The hardship and torment that prostitutes encounter in the industry will also be expounded. These concepts along with rape will be explored in Naguib Mahfouz's novels