• Title/Summary/Keyword: Load current control

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Fuzzy-based Processor Allocation Strategy for Multiprogrammed Shared-Memory Multiprocessors (다중프로그래밍 공유메모리 다중프로세서 시스템을 위한 퍼지 기반 프로세서 할당 기법)

  • 김진일;이상구
    • Journal of the Korean Institute of Intelligent Systems
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    • v.10 no.5
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    • pp.409-416
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    • 2000
  • In the shared-memory mutiprocessor systems, shared processing techniques such as time-sharing, space¬sharing, and gang-scheduling are used to improve the overall system utilization for the parallel operations. Recently, LLPC(Loop-Level Process Control) allocation technique was proposed. It dynamically adjusts the needed number of processors for the execution of the parallel code portions based on the current system load in the given job. This method allocates as many available processors as possible, and does not save any processors for the parallel sections of other later-arriving applications. To solve this problem, in this paper, we propose a new processor allocation technique called FPA(Fuzzy Processor Allocation) that dynamically adjusts the number of processors by fuzzifYing the amounts ofueeded number of processors, loads, and estimated execution times of job. The proposed method provides the maximum possibility of the parallism of each job without system overload. We compare the performances of our approaches with the conventional results. The experiments show that the proposed method provides a better performance.

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Low-earth orbiting satellite multi-output converter design and verification by using EDF modeling (EDF 모델링을 이용한 저궤도위성 다중 출력 컨버터 설계 및 검증)

  • Yun, SeokTeak;Yang, JeongHwan
    • Journal of Satellite, Information and Communications
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    • v.7 no.2
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    • pp.76-79
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    • 2012
  • Satellite power system is critical for mission design and survival operation. Accordingly power conversion circuit has to stable design and verify for operation condition change (load, voltage, thermal condition). however, multi-stage make complicate for modeling and get all state solution. In this paper present all state solution for multi-stage converter by using Extended Describing Function(EDF) modelling. EDF modelling has merit to solve complex circuit but it has limit too. Because of fundamental approximation, EDF modeling is not match all topology. Consequently, we verify passible topology for EDF modeling and stable design multi-stage converter.

The Development of Buck Type Electronic Ballast for 250W MHL and Dimming System (250W MHL용 Buck Type 전자식 안정기 및 Dimming 시스템 개발)

  • 박종연;박영길;정동열;김한수
    • The Transactions of the Korean Institute of Power Electronics
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    • v.7 no.1
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    • pp.30-40
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    • 2002
  • This paper studies the electronic ballast development for 250w MH lamps. We have improved the input power factor using a PFC IC. To provide the rating voltage required In the lamps, we have used the buck type dc-dc converter By this method, the stress of switching devices in inverter can be reduced. The inverter is the Full-Bridge type. To eliminate the acoustic resonance phenomena of MH lamps, we have added the high frequency sinewave voltage to the low frequency square-wave voltage to the lamp. We hove developed the igniter circuit using the L, C devices. We could control dimming of the lamp by varying the output voltage of the buck converter. The time of illuminating lamps and luminous intensity could be adjusted by season and time band. The buck converter output voltage can be controlled and the no load and over current situation were Protected by the development of the microprocessor Program.

Checkpoint-inhibition in ovarian cancer: rising star or just a dream?

  • Pietzner, Klaus;Nasser, Sara;Alavi, Sara;Darb-Esfahani, Silvia;Passler, Mona;Muallem, Mustafa Zelal;Sehouli, Jalid
    • Journal of Gynecologic Oncology
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    • v.29 no.6
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    • pp.93.1-93.11
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    • 2018
  • The introduction of checkpoint inhibitors revolutionized immuno-oncology. The efficacy of traditional immunotherapeutics, like vaccines and immunostimulants was very limited due to persistent immune-escape strategies of cancer cells. Checkpoint inhibitors target these escape mechanisms and re-direct the immune system to anti-tumor toxicity. Phenomenal results have been reported in entities like melanoma, where no other therapy was able to demonstrate survival benefit, before the introduction of immunotherapeutics. The first experience in ovarian cancer (OC) was reported for nivolumab, a fully human anti-programmed cell death protein 1 (PD1) antibody, in 2015. While the data are extraordinary for a mono-immunotherapeutic agent and very promising, they do not match up to the revolutionary results in entities like melanoma. The key to exceptional treatment response in OC, could be the identification of the most immunogenic patients. We hypothyse that BRCA mutation could be a predictor of improved response in OC. The underlying DNA-repair-deficiancy should result in increased immunogenicity because of higher mutational load and more neoantigen presentation. This hypothesis was not tested to date and should be subject to future trials. The present article gives an overview of the immunologic background of checkpoint inhibition (CI). It presents current data on nivolumab and other checkpoint-inhibitors in solid tumors and OC specifically and depicts important topics in the management of this novel substance group, such as side effect control, diagnostic PD-1/programmed cell death-ligand 1 (PD-L1) expression assessment and management of pseudoprogression.

Evaluation of Near Surface Mounted (NSM) FRP technique for strengthening of reinforced concrete slabs

  • Chunwei Zhang;M. Abedini
    • Advances in concrete construction
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    • v.16 no.4
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    • pp.205-216
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    • 2023
  • Concrete structures may become vulnerable during their lifetime due to several reasons such as degradation of their material properties; design or construction errors; and environmental damage due to earthquake. These structures should be repaired or strengthened to ensure proper performance for the current service load demands. Several methods have been investigated and applied for the strengthening of reinforced concrete (RC) structures using various materials. Fiber reinforced polymer (FRP) reinforcement is one of the most recent type of material for the strengthening purpose of RC structures. The main objective of the present research is to identify the behavior of reinforced concrete slabs strengthened with FRP bars by using near surface mounted (NSM) technique. Validation study is conducted based on the experimental test available in the literature to investigate the accuracy of finite element models using LS-DYNA to present the behavior of the models. A parametric analysis is conducted on the effect of FRP bar diameters, number of grooves, groove intervals as well as width and height of the grooves on the flexural behavior of strengthened reinforced slabs. Performance of strengthening RC slabs with NSM FRP bars was confirmed by comparing the results of strengthening reinforced slabs with control slab. The numerical results of mid-span deflection and stress time histories were reported. According to the numerical analysis results, the model with three grooves, FRP bar diameter of 10 mm and grooves distances of 100 mm is the most ideal and desirable model in this research. The results demonstrated that strengthening of reinforced concrete slabs using FRP by NSM method will have a significant effect on the performance of the slabs.

Impact of openings on the structural performance of ferrocement I-Beams under flexural loads

  • Yousry B.I. Shaheen;Ghada M. Hekal;Ayman M. Elshaboury;Ashraf M. Mahmoud
    • Structural Engineering and Mechanics
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    • v.90 no.4
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    • pp.371-390
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    • 2024
  • Investigating the impact of openings on the structural behavior of ferrocement I-beams with two distinct types of reinforcing metallic and non-metallic meshes is the primary goal of the current study. Up until failure, eight 250x200x2200 mm reinforced concrete I-beams were tested under flexural loadings. Depending on the kind of meshes used for reinforcement, the beams are split into two series. A control I-beam with no openings and three beams with one, two, and three openings, respectively, are found in each series. The two series are reinforced with three layers of welded steel meshes and two layers of tensar meshes, respectively, in order to maintain a constant reinforcement ratio. Structural parameters of investigated beams, including first crack, ultimate load, deflection, ductility index, energy absorption, strain characteristics, crack pattern, and failure mode were reported. The number of mesh layers, the volume fraction of reinforcement, and the kind of reinforcing materials are the primary factors that vary. This article presents the outcomes of a study that examined the experimental and numerical performance of ferrocement reinforced concrete I-beams with and without openings reinforced with welded steel mesh and tensar mesh separately. Utilizing ANSYS-16.0 software, nonlinear finite element analysis (NLFEA) was applied to illustrate how composite RC I-beams with openings behaved. In addition, a parametric study is conducted to explore the variables that can most significantly impact the mechanical behavior of the proposed model, such as the number of openings. The FE simulations produced an acceptable degree of experimental value estimation, as demonstrated by the obtained experimental and numerical results. It is also noteworthy to demonstrate that the strength gained by specimens without openings reinforced with tensar meshes was, on average, 22% less than that of specimens reinforced with welded steel meshes. For specimens with openings, this value is become on average 10%.

GMPLS based Functional Models and Connection Admission Control Algorithms for Optical Burst Switched Networks (광 버스트 교환 망을 위한 GMPLS 기반 기능 모델과 연결 수락 제어 알고리즘)

  • 소원호;노선식;김영천
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.7B
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    • pp.585-597
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    • 2004
  • In this paper, we propose the functional models of optical burst switching (OBS) routers to apply GMPLS (Generalized Multiprotocol Label Switching) to optical networks based on OBS. In addition, we introduce a connection admission control (CAC) algorithms which are operated in this models and can accommodate the required QoS. Firstly, the characteristics of current GMPLS and OBS for the optical Internet are basically considered. With this consideration, the models are proposed to accept OBS features which include the recognition of data boundary with control information and the statistical multiplexing in terms of bursts. Secondly, we use an offset time decision (OTD) algorithm on behalf of controlling the connection admission with taking QoS parameters such as burst loss rate(BLR) and service-differentiation ratio(SDR) into consideration. The proposed CAC algorithms use the offered load of LSP (Label Switched Path), wavelength information, and QoS parameters as inputs of OTD algorithm. A call setup request will be accepted when the offset time decided by OTD algorithm is reasonable for guaranteeing its requested QoS. Simulation is used for performance evaluation. Results show the proposed schemes can guarantee the required QoS and those are better than the previous one in terms of channel utilization.

Position Control of a Pneumatic Cylinder Actuator using PLC and Proximity Sensors (공압 실린더 액츄에이터 위치제어)

  • Kwon, Soon-Hong;Choi, Won-Sik;Chung, Sung-Won;Park, Jong-Min;Kwon, Soon-Goo;So, Jung-Duk
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.6
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    • pp.50-55
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    • 2011
  • The fluid power products are widely used in current industrial area such as automation of products and equipment assembly, high-tech machine tool, aircraft, train, and etc. As the development of industry is in progress, the development of the fluid power products is demanding and it is required in every industrial area. This research proposed a pneumatic system to evaluate displacement accuracy of the pneumatic actuator without external load and to analyze capability of integration of the valve system. The pneumatic system consisted of a combination of pneumatic actuator, four two-port valves, two three-port valves, two pressure valve, a check valve, two proximity sensors, and a program logic controller (PLC). The position controller is based on the PLC connected with the proximity sensors. The maximum air pressure applied for tests was $49.05N/cm^2$ and the displacement accuracy of a stroke was measured using a dial gauge. The supply- and discharge-side of air pressure and the length of the stroke of the pneumatic cylinder were varied The test of the position control of the pneumatic cylinder was carried out 50 times at each supply- and discharge-side air pressure of 24.53/34.34, 29.43/39.24, 34.34/44.15, and $39.24/49.05N/cm^2$ and replicated three times. The accuracy of the displacement of the pneumatic cylinder stroke increased as the supply- and discharge-side of air pressure increased with the stroke length of 133mm. Also the displacement accuracy increased as the stroke length increased with the fixed supply- and discharge-side of air pressure of the pneumatic cylinder as 34.34 and $44.15N/cm^2$, respectively. The most accurate displacement of the pneumatic cylinder was obtained at the supplyand discharge-side of air pressure of 39.24 and $49.05N/cm^2$, respectively, and strokes of 170 and 190mm.

GMPLS based Functional Models and Connection Admission Control Algorithms for Optical Burst Switched Networks (광 버스트 교환 망을 위한 GMPLS 기반 기능 모델과 연결 수락 제어 알고리즘)

  • So, Won-Ho;Roh, Sun-Sik;Kim, Young-Chon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.9B
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    • pp.778-790
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    • 2004
  • In this paper, we propose the functional models of optical burst switching (OBS) routers to apply GMPLS (Generalized Multiprotocol Label Switching) to optical networks based on OBS. In addition, we introduce a connection admission control (CAC) algorithms which are operated in this models and can accommodate the required QoS. Firstly, the characteristics of current GMPLS and OBS for the optical Internet are basically considered. With this consideration, the models are proposed to accept OBS features which include the recognition of data bounda η with control information and the statistical multiplexing in terms of bursts. Secondly, we use an offset time decision (OTD) algorithm on behalf of controlling the connection admission with taking QoS parameters such as burst loss rate(BLR) and service-differentiation ratio(SDR) into consideration. The proposed CAC algorithms use the offered load of LSP (Label Switched Path), wavelength information, and QoS parame ‘ ers as inputs of OTD algorithm. A call setup request will be accepted when the offset time decided by OTD algorithm is reasonable for guaranteeing its requested QoS. Simulation is used for performance evaluation Results show the proposed schemes can guarantee the required QoS and those are better than the previous one in terms of channel utilization.

Violation Detection of Application Network QoS using Ontology in SDN Environment (SDN 환경에서 온톨로지를 활용한 애플리케이션 네트워크의 품질 위반상황 식별 방법)

  • Hwang, Jeseung;Kim, Ungsoo;Park, Joonseok;Yeom, Keunhyuk
    • The Journal of Korean Institute of Next Generation Computing
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    • v.13 no.6
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    • pp.7-20
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    • 2017
  • The advancement of cloud and big data and the considerable growth of traffic have increased the complexity and problems in the management inefficiency of existing networks. The software-defined networking (SDN) environment has been developed to solve this problem. SDN enables us to control network equipment through programming by separating the transmission and control functions of the equipment. Accordingly, several studies have been conducted to improve the performance of SDN controllers, such as the method of connecting existing legacy equipment with SDN, the packet management method for efficient data communication, and the method of distributing controller load in a centralized architecture. However, there is insufficient research on the control of SDN in terms of the quality of network-using applications. To support the establishment and change of the routing paths that meet the required network service quality, we require a mechanism to identify network requirements based on a contract for application network service quality and to collect information about the current network status and identify the violations of network service quality. This study proposes a method of identifying the quality violations of network paths through ontology to ensure the network service quality of applications and provide efficient services in an SDN environment.