Waste Of Power Consumption Research Articles

Study on hydrodynamics characteristics in a gas-liquid stirred tank with a self-similarity impeller based on CFD-PBM coupled model

BackgroundIn general, radial impeller has been the most widely employed for the gas-liquid mixing process in the stirred tank. However, gas cavities are easy to form behind the impeller blades, which results in the waste of power consumption, the limited gas handling capacity of impeller and the poor dispersion of gas. Based on self-similarity property of nonlinear theory, a type of self-similarity impeller was employed to strengthen gas-liquid dispersion process in this work. MethodsThe hydrodynamics of gas-liquid dispersion process in a stirred tank with Rushton turbine and self-similarity impeller were comparatively investigated by computational fluid dynamics (CFD) simulation combined with a population balance model (PBM). The gas holdup distribution, gas cavities, relative power demand (RPD), bubble size distribution and turbulent intensity analysis in the gas-liquid dispersion process were predicted. Significant findingsResults showed that self-similarity impeller could destroy the gas cavity structure, reduce the negative pressure zone and gas accumulation, enhance the relative power demand (RPD) and improve the uniformity of gas holdup distribution compared with Rushton turbine, and the gas-liquid mixing efficiency can be further improved with the increase of the self-similar iteration number of self-similarity impeller. The proper increase of impeller speed was beneficial to overcome gas flooding and improve the gas-liquid two phase dispersion uniformity. The increase of gas flow rate obviously increased the gas holdup in liquid phase. Meanwhile, self-similarity impeller could increase the uniformity of bubble size compared with Rushton turbine, and increasingly so with the increase of self-similar iteration number of self-similarity impeller. The uniformity of bubble size was improved with the increase of impeller speed and was decreased with the increase of gas flow rate. In addition, self-similarity impeller could significantly enhance the turbulent intensity and turbulent kinetic energy dissipation rate by the jet flows through the concave-convex edges, which was beneficial to the gas dispersion process.

Optimization of Data Communication on Air Control Device Based on Internet of Things with Application of HTTP and MQTT Protocols

In this research, we proposed ALDEBARAN (Air Control Device Based on Internet of Things), that is, a device the HTTP protocol which can be applied as a protocol to communicate with the IoT ANTARES (Internet of Things Application and Technology Platform as your Reliable Solution) platform. Wi-Fi connectivity is needed to build a communication between devices and platforms, also to sends data continuously. Because the HTTP has a high overhead protocol resulting in waste of power consumption, so it needs to be optimized. The focus of this research is to optimize data communications on our device to create data communication and power saving efficiently. The method used is implementing the HTTP and MQTT protocols that are combined with several data transmission algorithms. Parameters such as latency and current consumption are compared and analysed to obtain the most optimal combination of protocols and algorithms. The result of this research is that MQTT protocol can be applied to our device and data communication with our scheme becomes more optimal.

An Efficient Implementation of the Bellman-Ford Algorithm for Kepler GPU Architectures

Finding the shortest paths from a single source to all other vertices is a common problem in graph analysis. The Bellman-Ford's algorithm is the solution that solves such a single-source shortest path (SSSP) problem and better applies to be parallelized for many-core architectures. Nevertheless, the high degree of parallelism is guaranteed at the cost of low work efficiency, which, compared to similar algorithms in literature (e.g., Dijkstra's) involves much more redundant work and a consequent waste of power consumption. This article presents a parallel implementation of the Bellman-Ford algorithm that exploits the architectural characteristics of recent GPU architectures (i.e., NVIDIA Kepler, Maxwell) to improve both performance and work efficiency. The article presents different optimizations to the implementation, which are oriented both to the algorithm and to the architecture. The experimental results show that the proposed implementation provides an average speedup of $5 \times$ higher than the existing most efficient parallel implementations for SSSP, that it works on graphs where those implementations cannot work or are inefficient (e.g., graphs with negative weight edges, sparse graphs), and that it sensibly reduces the redundant work caused by the parallelization process.

Low-Power Parallel Chien Search Architecture Using a Two-Step Approach

This brief proposes a new power-efficient Chien search (CS) architecture for parallel Bose–Chaudhuri–Hocquenghem (BCH) codes. For syndrome-based decoding, the CS plays a significant role in finding error locations, but exhaustive computation incurs a huge waste of power consumption. In the proposed architecture, the searching process is decomposed into two steps based on the binary matrix representation. Unlike the first step accessed every cycle, the second step is activated only when the first step is successful, resulting in remarkable power saving. Furthermore, an efficient architecture is presented to avoid the delay increase in critical paths caused by the two-step approach. Experimental results show that the proposed two-step architecture for the BCH (8752, 8192, 40) code saves power consumption by up to 50% compared with the conventional architecture.

기회주의적인 중계기 사용에 대한 협력 다이버시티의 성능 분석

Abstract The data forwarding transmission is an important function of the relay in cooperative communication in wireless communication systems. However, additional relay cause the waste of power consumption and cost. Therefore, in this paper, we consider how to use the user mobile devices in stead of relays to deal with this problem. In this paper, we proposed the protocol that divide each relay into two states of idle and non-idle. The receiver has two functions of base station and user mobile device. In this case, it is possible that no additional cost, and improve the spectral efficiency and network capacity. We verified BER performance for the proposed protocol over Rayleigh fading through Monte-Carlo simulation. Key Words : Cooperative Communication, Relay Using Scheme, Decode and Forward, Maximum Ratio Combining * 준회원, 울산대학교 전기공학부 ** 정회원, 울산대학교 전기전자정보시스템공학부(교신저자)접수일자 2014년 5월 7일, 수정완료 2014년 6월 7일 게재확정일자 2014년 6월 13일Received: 7 May, 2014 / Revised: 7 June, 2014 Accepted: 13 June, 2014