Indonesian Journal of Electrical Engineering and Informatics (IJEEI)
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Multiple-Access Technology of Choice In 3GPP LTE
Third-Generation Partnership Project (3GPP) standardizes an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) as air interface in its release 8 LTE. Orthogonal Frequency Division Multiple Access(OFDMA) and Single Carrier-Frequency Division Multiple Access(SC-FDMA)are key technologies for the air interface of mobile broadband systems.It is evident that mobile broadband access technologies are reaching a commonality in the air interface and networking architecture; they are being converged to an IP-based network architecture with OFDMA based air interface technology. The air interface of E-UTRAN is based on OFDMA in downlink and SC-FDMA in the uplink, making it possible to efficiently utilize bandwidth due to the orthogonally between sub-carriers and by assigning subsets of sub-carriers to individual users which allows for simultaneous data rate transmission from several users and differentiated quality of service for each user. In this paper, wehighlight the technologies behindOFDMA and SC-FDMA and also carry out performance comparison of the two air interface technologies. We brieflydescribe the 3GPP LTE standard, and its implementation using OFDMA and SC-FDMA technology
Fuzzy Control of Yaw and Roll Angles of a Simulated Helicopter Model Includes Articulated Manipulators
Fuzzy logic controller (FLC) is a heuristic method by If-Then Rules which resembles human intelligence and it is a good method for designing Non-linear control systems. In this paper, an arbitrary helicopter model includes articulated manipulators has been simulated with Matlab SimMechanics toolbox and then we designed a fuzzy controller for its yaw and roll angles when the manipulators are moving for a task. Results reveal that a simple FLC can control this complex system well
Problems of Choquet Integral Practical Applications
Choquet integral with respect to fuzzy measure is a generalization of weighted arithmetic mean aggregation operator. It allows taking into account the phenomenon of dependence between criteria. Due to this it is possible to reflect the expert knowledge more accurately without making the model simplification which is the assumption of independence of the aggregation criteria. The problems of Choquet fuzzy integral applications and possible ways of overcoming them are discussed. Practical applications for this relatively new apparatus are reviewed
Comparative Study on New AQM Mechanisms for Congestion Control
As usage of network goes increasing day by day, managing network traffic becomes a very difficult task. It is important to avoid high packet loss rates in the Internet. Congestion is the one of the major issue in the present networks. Congestion Control is one of the solutions adopted to solve the congestion issue and to control it. Numbers of queue management algorithms are proposed for congestion control and to reduce high packet loss rates. Active Queue Management (AQM) is one such mechanism which provides better control over congestion. In this paper a study is made on recent load based AQM techniques that are proposed and its merits and shortfall is presented
Approximations of Fuzzy Systems
A fuzzy system can uniformly approximate any real continuous function on a compact domain to any degree of accuracy. Such results can be viewed as an existence of optimal fuzzy systems. Li-Xin Wang discussed a similar problem using Gaussian membership function and Stone-Weierstrass Theorem. He established that fuzzy systems, with product inference, centroid defuzzification and Gaussian functions are capable of approximating any real continuous function on a compact set to arbitrary accuracy. In this paper we study a similar approximation problem by using exponential membership function
Survey on Wireless Sensor Networks for Reliable Life Services and Other Advanced Applications
Wireless is an old technology; however with the advancement of science and technology it has enabled us to send signals to one or more devices without tangible wire connections and reduced complexity. The increasing human needs have lead to the integration of different technologies into a single unit and Wireless Sensor Network (WSN) is one such integration where sensors are integrated with wireless system to form a network. This network is used for a plethora of applications in sectors like defence, agriculture, medical, environment and industry