• Title/Summary/Keyword: Optimal Operation

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Development of a Control Algorithm for Automatic Ventilation (환기창 자동제어용 제어 알고리즘 개발)

  • 박규식;이기명
    • Journal of Bio-Environment Control
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    • v.6 no.4
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    • pp.242-249
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    • 1997
  • Environmental control operations have been considerably contributed to the reduction of labor cost in both plastic film and glass greenhouses since government supported projects were begun. However, some problems are still remaining on the optimal environmental control and excessive operation due to an inflexible software regulating ventilation gear - reducers. The unadjustable software caused the damage of ventilation system, resulting in heat stresses of crops. This study was performed to develop a ventilation software controlling the vent opening level, opening sequence, based on the wind direction, and control interval according to the difference between ambient and set- up temperatures. The software included a beeper system alarming urgent cases, while a manager was remote from the greenhouse. A compatible hardware with the software was also developed by using a low-cost diffused DSP controller.

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The Design of Self Testing Comparator (자체시험(Self-Testing) 특성을 갖는 비교기(Comparator) 설계)

  • 양성현;이상훈
    • Journal of the Korea Computer Industry Society
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    • v.2 no.2
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    • pp.219-228
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    • 2001
  • This paper presents the implementation of comparator which are Fail-Safe with respect to faults caused by any single physical defect likely to occur in NMOS and CMOS integrated circuit. The goal is to use it at the Fail-Safe system. First, a new fault model for PLA(Programmable Logic Array) is presented. This model reflects several physical defects in VLSI circuits. It focuses on designs based on PLA because VLSI chips are far too complex to allow detailed analysis of all the possible physical defects that can occur and of the effects on the operation of the circuit. Second, this paper show that these design, which was implemented with 2 level AND_ORor NOR-NOR circuit, are optimal in term of size. And it also present a formal proof that a comparator implemented as NOR-NOR PLA, based on these design, is self-testing with respect to most single faults in the presented fault model. Finally, it discuss the application of the self-testing comparator as a building block for implementing Fail-Safe Adder.

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Development of Critical Paths for Appendectomy (표준 진료 지침서(Critical Paths) 개발에 관한 연구 - 충수절제술(Appendectomy) 환자용 -)

  • Kim, Yong-Soon;Park, Jee-Won;Park, Yon-Ok;Cho, Eun-Sook;Kim, Myung-Wook
    • Quality Improvement in Health Care
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    • v.2 no.2
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    • pp.32-45
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    • 1996
  • Background : A critical path defines an optimal sequencing and timing of interventions by physicians, nurses, and other staff for a particular diagnosis or procedure, designed to better utilize resources, maximize quality of care, and minimize delays. It can be thought of as a visualization of the patient care process. In this study, a review of appendectomy patient records was undertaken to identify a critical path for the management of this treatment. Methods: For this study, records of patients under 15 or over 65 years of age were excluded ; cases where the patient was pregnant, or where complications developed were also excluded. The remaining 21 cases were divided into two categories according to the indication for appendectomy : for acute appendicitis, and for perforated appendix or drainage of periappendical abscess. The time frame for the review was from patient examination immediately prior to operation, through discharge. The study team was composed of a surgeon, research head nurse, education head nurse, surgical part head nurse, and medical recorder. Following their review of the 21 charts, the team determined an appropriate progression and schedule for an appendectomy. Result : Through the chart and literature review, the following aspects of the care process were identified as typical and tracked : monitoring/assessment, treatment, lines/drains, medication, activity, diet, tests and patient education. Conclusion : From this study, the design team determined two separate critical paths : one for appendectomy only, and one for appendectomy plus drainage. Next, these paths must be validated and fine-tuned through clinical implementation. In addition, a comparison of our design with the critical paths determined at other hospitals would be extremely valuable for advancing research in this area. Lastly, the critical path approach to improving patient care and maximizing hospital resources should be applied to other procedures.

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Surgery for Bilateral Large Intracranial Traumatic Hematomas : Evacuation in a Single Session

  • Kompheak, Heng;Hwang, Sun-Chul;Kim, Dong-Sung;Shin, Dong-Sung;Kim, Bum-Tae
    • Journal of Korean Neurosurgical Society
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    • v.55 no.6
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    • pp.348-352
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    • 2014
  • Objective : Management guidelines for single intracranial hematomas have been established, but the optimal management of multiple hematomas has little known. We present bilateral traumatic supratentorial hematomas that each has enough volume to be evacuated and discuss how to operate effectively it in a single anesthesia. Methods : In total, 203 patients underwent evacuation and/or decompressive craniectomies for acute intracranial hematomas over 5 years. Among them, only eight cases (3.9%) underwent operations for bilateral intracranial hematomas in a single session. Injury mechanism, initial Glasgow Coma Scale score, types of intracranial lesions, surgical methods, and Glasgow outcome scale were evaluated. Results : The most common injury mechanism was a fall (four cases). The types of intracranial lesions were epidural hematoma (EDH)/intracerebral hematoma (ICH) in five, EDH/EDH in one, EDH/subdural hematoma (SDH) in one, and ICH/SDH in one. All cases except one had an EDH. The EDH was addressed first in all cases. Then, the evacuation of the ICH was performed through a small craniotomy or burr hole. All patients except one survived. Conclusion : Bilateral intracranial hematomas that should be removed in a single-session operation are rare. Epidural hematomas almost always occur in these cases and should be removed first to prevent the hematoma from growing during the surgery. Then, the other hematoma, contralateral to the EDH, can be evacuated with a small craniotomy.

Effects of the electronic expansion valve and variable velocity compressor on the performance of a refrigeration system

  • Lago, Taynara G.S.;Ismail, Kamal A.R.;Nobrega, Claudia R.E.S.;Moura, Luiz F.M.
    • Advances in Energy Research
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    • v.7 no.1
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    • pp.1-19
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    • 2020
  • Energy consumption of air-conditioning and refrigeration systems is responsible for about 25 to 30% of the energy demand especially in hot seasons. This equipment is mostly electricity dependent and their use in principle affects negatively the environment. Enhancing the energy efficiency of the existing equipment is important as one of the measures to reduce environment impacts. This paper reports the results of an experimental study to evaluate the impacts of the use electronic expansion valve and variable velocity compressor on the performance of vapor compression refrigeration system. The experimental rig is composed of two independent circuits one for the vapor compression system and the other is the secondary fluid system. The vapor compression system is composed of a forced air condenser unit, evaporator, hermetic compressor and expansion elements, while the secondary system has a pump for circulating the secondary fluid, and an air conditioning heat exchanger. The manufacturer's data was used to determine the optimal points of operation of the system and consequently tests were done to evaluate the influence of variation of the compressor velocity and the opening of the expansion device on the performance of the refrigeration system. A fuzzy logic model was developed to control the rotational velocity of the compressor and the thermal load. Fuzzy control model was made in LabVIEW software with the objective of improving the system performance, stability and energy saving. The results showed that the use of fuzzy logic as a form of control strategy resulted in a better energy efficiency.

Ethanol Production from Glycerol Using Immobilized Pachysolen tannophilus During Microaerated Repeated-Batch Fermentor Culture

  • Cha, Hye-Geun;Kim, Yi-Ok;Choi, Woon Yong;Kang, Do-Hyung;Lee, Hyeon-Yong;Jung, Kyung-Hwan
    • Journal of Microbiology and Biotechnology
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    • v.25 no.3
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    • pp.366-374
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    • 2015
  • Herein, we established a repeated-batch process for ethanol production from glycerol by immobilized Pachysolen tannophilus. The aim of this study was to develop a more practical and applicable ethanol production process for biofuel. In particular, using industrial-grade medium ingredients, the microaeration rate was optimized for maximization of the ethanol production, and the relevant metabolic parameters were then analyzed. The microaeration rate of 0.11 vvm, which is far lower than those occurring in a shaking flask culture, was found to be the optimal value for ethanol production from glycerol. In addition, it was found that, among those tested, Celite was a more appropriate carrier for the immobilization of P. tannophilus to induce production of ethanol from glycerol. Finally, through a repeated-batch culture, the ethanol yield (Ye/g) of 0.126 ± 0.017 g-ethanol/g-glycerol (n = 4) was obtained, and this value was remarkably comparable with a previous report. In the future, it is expected that the results of this study will be applied for the development of a more practical and profitable long-term ethanol production process, thanks to the industrial-grade medium preparation, simple immobilization method, and easy repeated-batch operation.

An Efficient Evolutionary Algorithm for Optimal Arrangement of RFID Reader Antenna (RFID 리더기 안테나의 최적 배치를 위한 효율적인 진화 연산 알고리즘)

  • Soon, Nam-Soon;Yeo, Myung-Ho;Yoo, Jae-Soo
    • The Journal of the Korea Contents Association
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    • v.9 no.10
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    • pp.40-50
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    • 2009
  • Incorrect deployment of RFID readers occurs reader-to-reader interferences in many applications using RFID technologies. Reader-to-reader interference occurs when a reader transmits a signal that interferes with the operation of another reader, thus preventing the second reader from communicating with tags in its interrogation zone. Interference detected by one reader and caused by another reader is referred to as a reader collision. In RFID systems, the reader collision problem is considered to be the bottleneck for the system throughput and reading efficiency. In this paper, we propose a novel RFID reader anti-collision algorithm based on evolutionary algorithm(EA). First, we analyze characteristics of RFID antennas and build database. Also, we propose EA encoding algorithm, fitness algorithm and genetic operators to deploy antennas efficiently. To show superiority of our proposed algorithm, we simulated our proposed algorithm. In the result, our proposed algorithm obtains 95.45% coverage rate and 10.29% interference rate after about 100 generations.

Design and Implementation of a RFID Reader Antenna Optimal Arrangement System (RFID 리더기 안테나 최적 배치 시스템의 설계 및 구현)

  • Soon, Nam-Soon;Yeo, Myung-Ho;Yoo, Jae-Soo
    • The Journal of the Korea Contents Association
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    • v.9 no.10
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    • pp.67-74
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    • 2009
  • Incorrect deployment of RFID readers occurs reader-to-reader interferences in many applications using RFID technologies. Reader-to-reader interference occurs when a reader transmits a signal that interferes with the operation of another reader, thus preventing the second reader from communicating with tags in its interrogation zone. Interference detected by one reader and caused by another reader is referred to as a reader collision. In RFID systems, the reader collision problem is considered to be the bottleneck for the system throughput and reading efficiency. In this paper, we propose a novel RFID reader anti-collision algorithm based on evolutionary algorithm(EA). First, we analyze characteristics of RFID antennas and build database. Also, we propose EA encoding algorithm, fitness algorithm and genetic operators to deploy antennas efficiently. To show superiority of our proposed algorithm, we simulated our proposed algorithm. In the result, our proposed algorithm obtains 95.45% coverage rate and 10.29% interference rate after about 100 generations.

Numerical Study for the Optimal Operation of Semi Dry Reactor(SDR) (SDR 반응의 운전 최적화를 위한 전산 해석)

  • Park, Ki-Woo;Jung, Yu-Jin;Jeong, Moon-Heon;Hong, Sung-Gil;Jung, Jong-Hyeon;Lim, Ki-Hyuk;Shon, Byung-Hyun
    • Proceedings of the KAIS Fall Conference
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    • 2012.05a
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    • pp.426-430
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    • 2012
  • 본 연구에서는 3차원 수치 해석 기법으로 SDR 반응기 내 유동 특성을 모사하여 유동 분포 및 체류 시간등을 확인하고 혼합 특성 개선을 위한 방법에 대해 연구하였다. 본 연구 대상 SDR 반응기는 입구 덕트와 반응기 본체의 접속 구간에 가이드 베인(Guide vane)이 설치되어 있고 그 바로 하부 지점에 흡수제를 분무하는 노즐이 설치되어 있다. 이는 처리가스가 반응기로 유입될 때 가이드 베인에 의해 선회류를 형성하여 분무된 흡수제와의 혼합을 촉진시키기 위한 목적으로 설치하였다. 시간당 1,971$m^3/min$ at $260^{\circ}C$의 처리가스가 반응기 상부로 유입되어 가이드 베인을 거쳐 선회류를 형성한 후흡수제와 혼합되어 하부로 배출되는 구조이다. 유동 특성을 분석한 결과, 처리가스가 반응기 중앙으로 강하게 편중되고 있었으며 반응기 양 측면으로 부상 기류가 형성되고 있음을 확인할 수 있다. 또한 강한 편류에 의해 체류시간도 매우 짧은 것으로 판단되는 바, 가이드 베인의 기류 안내 각도가 적합하지 못함을 확인할 수 있었다. 이는 곧 혼합 특성 저하에 따른 미반응 액적의 다량 발생과 함께 고착에 의한 스케일 형성 가능성이 매우 클 것으로 예상되므로 혼합 특성을 개선할 수 있는 설계 변경이 필요할 것으로 판단되었다. 따라서 편류를 해소하고 노즐 근처에서의 체공시간을 확보할 수 있도록 가이드 베인의 안내 각도를 더 크게 변경한 결과, 기존 설계상에서 본체 중앙에 형성되는 편류가 해소되고 선회류의 전개 각도가 커지면서 체류시간 역시 약 5초 이상으로 유지되고 있음을 확인할 수 있었다. 따라서 가이드 베인의 각도만 변경하더라도 본체 형상의 추가적인 변경없이 유동의 혼합 특성을 개선시킬 수 있을 것으로 판단되었다.

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A Study on Realization of System in Wireless Location Awareness Technology Using Ubiquitous Active RFID (Active RFID를 이용한 실내 무선 위치 인식 기반 스마트 센서 빌딩 구현에 관한 연구)

  • Jung, Chang Duk
    • Journal of Intelligence and Information Systems
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    • v.12 no.3
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    • pp.83-93
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    • 2006
  • This paper is wireless location awareness technology using RFID. We investigates the Location of the received Signal strength reported by RF Analyses of the data are performed to understand the underlying features of location fingerprints. The system is performed factors the extreme environmental Emit signal, which consists of a unique 5000 Terminals. The Location Service have become very popular in many service industries, purchasing and distribution logistics, industry, manufacturing companies and a parking place. The Technically optimal Solution would be the storage of Intelligence information in the most common form of electronic data-carrying device in use in everyday life is the smart card based upon a contact field (telephone smart card, bank cards). The method of an indoor positioning experiment system is compared using measured Location data and a charge of service. The result of research showed the following: first, to check out the mechanism between benefit of system installation and operation of Active RFID. Second, it contributed on indoor wireless location intelligence system efficiency.

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