• Title/Summary/Keyword: Prime factors

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A study on the arrangement of integrated power system for warship (함정의 통합 전력시스템 구성에 관한 연구)

  • Baek, Hyun-Min;Jung, Kyun-Sik;Lee, Myung-Ho;Choi, Jae-Sung
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.9
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    • pp.1070-1074
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    • 2014
  • According to IEEE 1662(2009), IPS is a power system where all prime movers produce electrical power that is shared among propulsion, mission, and ship service loads. Discriminating attributes of integrated power systems are flexibility of movers' arrangements, mechanical decoupling between prime movers and propulsors, an increased level of energy conversion and transmission redundancy, and flexibility of redistributing available electrical power for future electronic weapons. IPS could have various steps of power that can be produced at optimal load of movers. In this study, an evaluation method for optimal arrangement of movers was investigated when an IPS warship is projected. The two factors are utilized for the quantitative analysis which are the weight of system as the fighting power and the fuel consumption per year as the economic feasibility. And also the ways for arrangement of system were studied according to existence of small diesel generator. The evaluation method that decides the optimization level is based on the DEA(Data Envelopment Analysis)

Brain Plasticity and Stroke Rehabilitation (뇌가소성과 뇌졸중 재활)

  • Kim, Sik-Hyun
    • PNF and Movement
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    • v.6 no.2
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    • pp.39-50
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    • 2008
  • Purpose : This article reviewed the advances in the understanding of the effect of motor rehabilitation and brain plasticity on functional recovery after CNS damage. Methods : This is literature study with Pubmed, Medline and Science journal. Results : The inability of CNS neurons to regenerate is largely associated with nonneuronal aspects of the CNS environment. Especially, this neuronal growth inhibition is mediated by myelin associated glycoprotein, olygodendrocyte-myelin glycoprotein, and NOGO. Enriched environment, motor learning, forced limb use have been utilized in scientific studies to promote functional reorganization and brain plasticity. Especially, enriched environment and motor enrichment may prime the brain to respond more adaptively to injury, in part by expressed neurotrophic factors. Conclusions : These reviews suggest that activity-induced neural plasticity occur in damaged brain areas in order to functional reorganization, where it could contribute to motor recovery, and represent a target for stroke rehabilitation.

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Knowledge-Based System for Optimum Propulsion Engine Selection of Ships (최적 박용엔진 선정을 위한 지식기반시스템)

  • Lee, Dong-Kon;Lee, Kyung-Ho;Lee, Kyu-Yeul;Lee, Chang-Euk
    • Journal of Korean Institute of Industrial Engineers
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    • v.19 no.3
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    • pp.3-10
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    • 1993
  • The main propulsion system may be the most complicated of the shipboard systems. Many factors such as fuel economy, weight, space, first cost, reliability, vibration and noise must be considered when selecting the prime mover of the main propulsion system for ships. An expert system is a computer program that represents and reasons with knowledge of some specialist subject with a view to solving problems or giving advice. Recently, it is being developed increasingly with wider applications in many industries. This paper describes development of knowledge-based system for main engine selection of ships using general purpose expert system development tool, Nexpert Object. Developed system is consist of ship performance estimation module such as resistance and propulsion, data base for main engine, knowledge base for main engine selection in Nexpert Object and graphic user interface.

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The Perception-Based Study of a Weak Syllable in English Words Containing Weak-Strong Pattern by Korean Learners (I) (약강구조를 포함하는 영어단어에 대한 영어학습자의 약음절 지각과 반응시간(I))

  • Shin Ji-Young;Kim Kee-Ho;Kim Hee-Sung
    • MALSORI
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    • no.57
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    • pp.31-42
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    • 2006
  • The purpose of this study is to observe how Korean learners perceive an English weak syllable in words containing WS syllable pattern. According to the automated discrimination task using E-Prime, the ratio of correct answer(%) and reaction time of the stimuli with same syllable patterns were respectively higher and faster than those with different syllable patterns. Specifically, in the stimuli with different syllable patterns, the frequency(familiarity) of stressed word succeeding weak syllable and whether the weak syllable had coda in it were two important factors in distinguishing between a word with and without weak syllable. Even though the high English proficiency Koreans had faster reaction time than the low English proficiency Koreans, all Korean learners had a difficulty in perceiving the weak syllable at the beginning of a word.

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Hardware-Saving Realizations of Interpolators and Decimators Using Periodically Time-Varying Coefficients

  • Ratansanya, San;Amornraksa, Thumrongrat;Tipakorn, Bundit
    • Proceedings of the IEEK Conference
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    • 2002.07b
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    • pp.860-863
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    • 2002
  • Realizations of multirate converters are proposed using periodically time-varying (PTV) structures. By exploiting the computational redundancy of the filtering operation in a multirate filter, it is possible to implement the filter with much less hardware. In the proposed implementations, several coefficients time-share in a periodic fashion the hardware of one multiply-and-add. Therefore, each multiply-and-add circuit performs different coefficient scalings at different time instants within a period. Compared to the direct form realization, the proposed realizations reduce the hardware of an interpolator and a decimator by a factor of approximately U and M, respectively, while retaining the same processing speed, where U and M are the upsampling and downsampling factors, respectively. The approach can be used to obtain realizations for sampling rate conversion by a rational factor of U/M, where U and M are relatively prime, in which case hardware reduction by a factor of approximately UM can be achieved.

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Influences of Prolonged Extracorporeal Circulation on Organ Function in Dogs (장시간의 체외순환이 생체에 미치는 영향)

  • 김의윤
    • Journal of Chest Surgery
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    • v.7 no.1
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    • pp.73-78
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    • 1974
  • Influences on organ function were studied in animals during prolonged extracorporeal circulation with a bubble type of oxygenator. More than six hours of total cardiopulmonary bypass was performed under mild hypothermia by means of an extracorporeal circulation system in five dogs. Obtained results were summarized as follows. 1. The renal function was not so impaired seriously until four hours of extracorporeal circulation. However, there was more serious impairment of renal function in this study when extracorporeal circulation was carried out for a period of five hours or more. 2. There was gradual hepatic damage during extracorporeal circulation and the damage was more significant after bypass for a period of five to six hours. 3. There was a significant decrease in serum K during bypass, irrespective of the pump oxygenator prime with a high K solution. The reason for this is complex and due to many factors, however, it was evidently related to serum glucose levels during extracorporal circulation.

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KOMPSAT EOC Grid Reference System

  • Kim, Youn-Soo;Kim, Yong-Seung;Benton, William
    • Proceedings of the KSRS Conference
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    • 1998.09a
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    • pp.349-354
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    • 1998
  • The grid reference system (GRS) has been useful for identifying the geographical location of satellite images. In this study we derive a GRS for the KOMPSAT Electro-Optical Camera (EOC) images. The derivation substantially follows the way that SPOT defines for its GRS, but incorporates the KOMPSAT orbital characteristics. The KOMPSAT EOC GRS (KEGRS) is designed to be a (K,J) coordinate system. The K coordinate parallel to the KOMPSAT ground track denotes the relative longitudinal position and the J coordinate represents the relative latitudinal position. The numbering of K begins with the prime meridian of K=1 with K increasing eastward, and the numbering of J uses a fixed value of J=500 at all center points on the equator with J increasing northward. The lateral and vertical intervals of grids are determined to be 12.5 km about at the 38$^{\circ}$ latitude to allow some margins for the value-added processing. The above design factors are being implemented in a satellite programming module of the KOMPSAT Receiving and Processing System (KRPS) to facilitate the EOC data collection planning over the Korean peninsula.

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Precise width control through the width spread compensation in hot strip mill (열간압연시 폭퍼짐 보상을 통한 폭정밀도 개선연구)

  • 천명식;이준정;문영훈
    • Transactions of Materials Processing
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    • v.8 no.2
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    • pp.200-207
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    • 1999
  • To increase dimensional accuracy of strip width, model to compensate width spread during roughing mill has been developed. To measure the amount of width spread during the production rolling more precisely, special roughing rolling procedures for the horizontal rolling and dog-bone rolling were designed in the actual production mill. From the operational data analysis, it is known that the prime factors influencing on the width spread were strip width, strip thickness, edging amount, number of pass and type of edger roll etc., Based upon the statistical analysis of rolling data, new models which can predict width spread during horizontal rolling and dog-bone rolling were developed and tested on the actual processing conditions for the reliability. The application test showed that newly developed model gave fairly accurate predictions on the width spread during roughing passes.

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Part Assembly Sequences for Human Assembler Postures (조립작업자의 동작과 자세를 고려한 조립순서결정)

  • Kim, Jyeo-Neon;Jeong, Seong-Han;Jee, Hae-Seong
    • Korean Journal of Computational Design and Engineering
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    • v.13 no.5
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    • pp.391-402
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    • 2008
  • Today's product development environment is characterized as abrupt changes in consumer needs and short lifecycle of the product, which requires manufacturing companies to be equipped with time-to-market and time-to-volume strategies as prime factors for the successful product launch on market. They especially need to bring a product to the market faster with smart methodologies that enable assembly manufacturers to efficiently simulate and manage part assembly information throughout product development process. The research in this paper provides n e-manufacturing methodology considering geometric constraints in order to decide assembly process sequences. The methodology organizies the part layout (position & orientation) in order to optimize human postures during the assembly processes. As the case studies, assembly parts for two commercial products have been generated as CAD models and analyzed for the desired solutions for part assembly sequences using the proposed methodology.

Stress and strain analysis of functionally graded plates with circular cutout

  • Dhiraj, Vikash Singh;Jadvani, Nandit;Kalita, Kanak
    • Advances in materials Research
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    • v.5 no.2
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    • pp.81-92
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    • 2016
  • Stress concentration is an interesting and essential field of study, as it is the prime cause of failure of structural parts under static load. In the current paper, stress and strain concentration factors in unidirectional functionally graded (UDFGM) plate with central circular cutout are predicted by carrying out a finite element study on ANSYS APDL platform. The present study aims to bridge the lacuna in the understandings of stress analysis in perforated functionally graded plates. It is found that the material variation parameter is an important criterion while designing a perforated UDFGM plate. By selecting a proper material variation parameter and direction of material gradation, the stress and strain concentrations can be significantly reduced.