• Title/Summary/Keyword: Power Saving Algorithm

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Full Data-rate Viterbi Decoder for DAB Receiver (최대 데이터율을 지원하는 DAB 수신기용 Viterbi 디코더의 설계)

  • 김효원;구오석;류주현;윤대희
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.6C
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    • pp.601-609
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    • 2002
  • The efficient Viterbi decoder that supports full data-rate output of DAB system was proposed. Viterbi decoder consumes lots of computational load and should be designed to be fast specific hardware. In this paper, SST scheme was adopted for Viterbi decoder with puncturing to reduced the power consumption. Puncturing vector tables are modified and re-arranged to be designed by a hardwired logic to save the system area. New re-scaling scheme which uses the fact that the difference of the maximum and minimum of the path metric values is bounded is proposed. The proposed re-scaling scheme optimizes the wordlength of path metric memory and greatly reduces the computational load for re-scaling by controlling MSB of path metric memory. Another saving of computation is done by proposed algorithm for branch metric calculation, which makes use of pre-calculated metric values. The designed Viterbi decoder was synthesized using SAMSUNG 0.35$\mu$ standard cell library and occupied small area and showed lower power consumption.

Efficient Tracking System for Passengers with the Detection Algorithm of a Stopping Vehicle (차량정차감지 알고리즘을 이용한 탑승자의 효율적 위치추적시스템)

  • Lee, Byung-Mun;Shin, Hyun-Ho;Kang, Un-Gu
    • Journal of Internet Computing and Services
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    • v.12 no.6
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    • pp.73-82
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    • 2011
  • The location-based service is emerging again to the public attention. The location recognition environment up-to-now has been studied with its focus only on a person, an object or a moving object. However, this study proposes a location recognition model that serves to recognize and track, in real time, multiple passengers in a moving vehicle. Identifying the locations of passengers can be classified into two classes: one is to use the high price terminal with GPS function, and the other is to use the economic price compact terminal without GPS function. Our model enables the simple compact terminal to provide effective location recognition under the on-boarding situation by transmitting messages through an interface device and sensor networks for a vehicle equipped with GPS. This technology reduces transmission traffic after detecting the condition of a vehicle (being parked or running), because it does not require transmission/receiving of information on the locations of passengers who are confined in a vehicle when the vehicle is running. Also it extends battery life by saving power consumption of the compact terminal. Hence, we carried out experiments to verify its serviceability by materializing the efficient tracking system for passengers with the detection algorithm of a stopping vehicle proposed in this study. Moreover, about 200 experiments using the system designed with this technology proved successful recognition on on-boarding and alighting of passengers with the maximum transmission distance of 12 km. In addition to this, the running recognition tests showed the test with the detection algorithm of a stopping vehicle has reduced transmission traffic by 41.6% compared to the algorithm without our model.

Operation Scheduling in a Commercial Building with Chiller System and Energy Storage System for a Demand Response Market (냉각 시스템 및 에너지 저장 시스템을 갖춘 상업용 빌딩의 수요자원 거래시장 대응을 위한 운영 스케줄링)

  • Son, Joon-Ho;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.8
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    • pp.312-321
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    • 2018
  • The Korean DR market proposes suppression of peak demand under reliability crisis caused a natural disaster or unexpected power plant accidents as well as saving power plant construction costs and expanding amount of reserve as utility's perspective. End-user is notified a DR event signal DR execution before one hour, and executes DR based on requested amount of load reduction. This paper proposes a DR energy management algorithm that can be scheduled the optimal operations of chiller system and ESS in the next day considering the TOU tariff and DR scheme. In this DR algorithm is divided into two scheduling's; day-ahead operation scheduling with temperature forecasting error and operation rescheduling on DR operation. In day-ahead operation scheduling, the operations of DR resources are scheduled based on the finite number of ambient temperature scenarios, which have been generated based on the historical ambient temperature data. As well as, the uncertainties in DR event including requested amount of load reduction and specified DR duration are also considered as scenarios. Also, operation rescheduling on DR operation day is proposed to ensure thermal comfort and the benefit of a COB owner. The proposed method minimizes the expected energy cost by a mixed integer linear programming (MILP).

Particle Swarm Optimization-Based Peak Shaving Scheme Using ESS for Reducing Electricity Tariff (전기요금 절감용 ESS를 활용한 Particle Swarm Optimization 기반 Peak Shaving 제어 방법)

  • Park, Myoung Woo;Kang, Moses;Yun, YongWoon;Hong, Seonri;BAE, KUK YEOL;Baek, Jongbok
    • Journal of IKEEE
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    • v.25 no.2
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    • pp.388-398
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    • 2021
  • This paper proposes a particle swarm optimization (PSO)-based peak shaving scheme using energy storage system (ESS) for electricity tariff reduction. The proposed scheme compares the actual load with the estimated load consumption, calculates the additional output power that the ESS needs to discharge additionally to reduce peak load, and adds the input. In addition, in order to compensate for the additional power, the process of allocating power to the determined point is performed, and an optimization that minimizes the average of the load expected at the active power allocations using PSO so that the allocated value does not affect the peak load. To investigated the performance of the proposed scheme, case study of small and large load prediction errors was conducted by reflecting actual load data and load prediction algorithm. As a result, when the proposed scheme is performed with the ESS charge and discharge control to reduce electricity tariff, even when the load prediction error is large, the peak load is successfully reduced, and the peak load reduction effect of 17.8% and electricity tariff reduction effect of 6.02% is shown.

A Study on the Development of the Engine Room Fan Control System and ERFCS Algorithm for Ships Energy Saving (선박 에너지 절감을 위한 기관실 팬 제어 시스템 구축 및 알고리즘에 관한 연구)

  • Kang, Young-Min;Oh, Jin-Seok
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.6
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    • pp.642-648
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    • 2015
  • Recently, there have been many studies pertaining to reducing energy consumption on ships. As part of those studies, the energy consumption of ships can be reduced by understanding and controlling the varying loads, excluding fixed loads. In existing ships, engine room fans are usually operated based on the actual experience of the crew without any special guidelines. To realize energy reduction, we investigate the characteristics of engine-room fans, and we propose an energy-management system called the engine room fan control system (ERFCS) and the ERFCS algorithm. The ERFCS controls the fan speed depending on the temperature and pressure, where one to four fans are operated depending on changes in the load. In addition, the minimum rotation speed of the engine-room fan was limited to 50% to prevent the surging phenomenon, which is due to fan damage or low pressure resulting from mechanical friction or heating at low fan speeds. We develop a fan control system simulation model using LabVIEW that is based on the proposed algorithm and ISO 8861. Finally, we perform simulations to confirm that operation of the proposed fan control system is possible using only 46.4% of the power required by the existing method.

Performance Analysis for Regenerative Energy Storage System in Kyoung-bu High Speed Railway (경부고속철도 회생 에너지 저장시스템 성능 분석)

  • Jang, Min-Ju;Jeon, Yong-Joo;Lho, Young Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.9
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    • pp.1391-1397
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    • 2015
  • Recently, various researches are conducted in the application of regenerative energy produced during the operation of an electric locomotive. Regenerative energy is produced by a generator in the brake procedure. The generator is operated by kinetic energy of an electric railroad using an electric motor. The process of producing regenerative energy varies with the current type of a railroad and its running condition. The quality of electric power can be improved and electric energy can be utilized effectively, especially in the use of an energy storage system (ESS). Thus, it is necessary to apply ESS into AC section and high speed railway. This study analyses the composition of the regenerative ESS equipment installed in Yong-Jeong sectioning post, operational principle, charge and discharge algorithm and energy efficiency. The analysis shows that CO2 emissions can be reduced about 0.5 ton per a day. In addition, ESS helps saving the energy and the compensation of the voltage drop caused by the operation of high speed train when it is installed at the end of the feeder section. The number of high speed train will be increased continuously related to the electrification rate. Therefore, applying the ESS to high speed railway is expected to solve the instability of the feeder voltage and the equipment capacity problem caused by the high speed trains.

An Energy Efficient Routing Scheme for Cluster-based WSNs (클러스터 기반 WSN에서 에너지 효율적인 라우팅 기법)

  • Song, Chang-Young;Kim, Seong-Ihl;Won, Young-Jin;Chung, Yong-Jin
    • 전자공학회논문지 IE
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    • v.47 no.3
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    • pp.41-46
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    • 2010
  • WSN, or Wireless Sensor Network, consists of a multitude of inexpensive micro-sensors. Because the batteries in sensor nodes can not be replaced once they are deployed, the life of a WSN is absolutely determined by the batteries. So, energy efficiency of a network is a critical factor for long-life operation. LEACH protocol which divides WSN into two groups is a typical routing protocol based on the clustering scheme for the efficient use of limited energy. It is composed of round units which are separated into set-up and steady state. In this paper we propose a power saving scheme to minimize set-up phase itself and to involve a data comparison algorithm. We evaluate the performance of the proposed scheme in comparison with original LEACH protocol. Simulation results validate our scheme has better performance in terms of the number of alive nodes as time evolves and average energy dissipated.

A Routing Method Considering Sensed Data in Wireless Sensor Networks (무선 센서 네트워크에서 데이터 센싱을 고려한 라우팅 기법)

  • Song, Chang-Young;Lee, Sang-Won;Cho, Seong-Soo;Kim, Seong-Ihl;Won, Young-Jin;Kang, June-Gill
    • 전자공학회논문지 IE
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    • v.47 no.1
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    • pp.41-47
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    • 2010
  • It is very important to prolong the lifetime of wireless sensor networks by using their limited energy efficiently, since it is not possible to change or recharge the battery of sensor nodes after deployment. LEACH protocol is a typical routing protocol based on the clustering scheme for the efficient use of limited energy. It is composed of a few clusters, which consist of head nodes and member nodes. Though LEACH starts from the supposition that all nodes have data transferred to a head, there must be some nodes having useless data in actual state. In this paper we propose a power saving scheme by making a member node dormant if previous sensed data and current data is same. We evaluate the performance of the proposed scheme in comparison with original clustering algorithms. Simulation results validate our scheme has better performance in terms of the number of alive nodes as time evolves.

Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.