• Title/Summary/Keyword: Linkage type

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Implementation and Application of Integrated Model for ALT(Accelerated Life Test) (ALT 통합모형의 적용 및 응용)

  • Choi, Sung-Woon
    • Proceedings of the Safety Management and Science Conference
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    • 2008.11a
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    • pp.153-160
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    • 2008
  • This paper presents the log likelihood function for integrated models for ALT such as exponential-general Eyring, Weibull-temperature and specific heat, lognormal-temperature and specific heat. Additionally this paper estimates the system reliability and mean time to failure(MTTF) for series, parallel, k of n, and standby system using ALT linkage parameter. Lastly this study designs three variable reliability acceptance sampling(RAS) plans such as type I, II censored test, sequential test by the use of integrated models for ALT.

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The Fault Current Limiting Characteristics According to Increase of Voltage in a Flux-Lock Type High-Tc Superconducting Fault Current Limiter (전압 증가에 따른 자속구속형 고온 초전도 전류제한기의 사고전류 제한 특성)

  • Cho, Yong-Sun;Park, Hyoung-Min;Lim, Sung-Hun;Park, Chung-Ryul;Han, Byoung-Sung;Choi, Hyo-Sang;Hyun, Ok-Bae;Hwang, Jong-Sung
    • Proceedings of the KIEE Conference
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    • 2004.11d
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    • pp.93-96
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    • 2004
  • In this paper, we analyzed the current limiting characteristics according to increase of source voltage in the flux-lock type high-Tc superconducting fault current limiter (SFCL). The flux-lock type SFCL consisted of two coils, which were wound in parallel each other through an iron core, and high-Tc superconducting (HTSC) element connected with coil 2 in series. The flux-lock type SFCL has the characteristics better in comparison with the resistive type SFCL because the fault current in the flux-lock type SFCL can be divided into two coils by the inductance ratio of coil 1 and coil 2. The fault current limiting operation of the flux-lock type SFCL can be different due to winding direction of the two coils. The winding method where the decrease of linkage flux between two coils in the accident happens is called the subtractive polarity winding and the winding method in case of the increase of linkage flux is called the additive polarity winding. The fault current limiting experiments according to the source voltage were performed for these two winding methods. Through the comparison and the analysis of the experimental data, we confirmed that the quench time was shorter, irrespective of the winding direction as the source voltage increased and that the fault current and the HTSC's resistance increased as the amplitude of the source voltage increased. The additive polarity winding made the fast quench time and the lower resistance of HTSC element in comparison with the subtractive polarity winding. The fault current of the subtractive polarity winding was larger than that of the additive polarity winding. In conclusion, we found that the additive polarity winding reduced the burden of SFCL because the quench time was shorter and the fault current was smaller than those of the subtractive polarity winding.

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Location and Linkages of Manufacturing in Jangyu-Myun, Kimhae-Gun (김해군 장유면의 공업입지와 지역적 연계)

  • Lim, Yeong-Dae
    • Journal of the Korean association of regional geographers
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    • v.4 no.1
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    • pp.99-120
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    • 1998
  • The purpose of this study is to clarify the industrialization process, and locational factors and linkages of manufacturing in Jangyu-Myun, a suburb of Metropolitan Pusan, toward which heavy decentralization of manufacturing from Pusan has been done. Hard data and soft data were used as the basic data. Hard data used for this study were both the statistical data which consists of the number of establishments and employee classified by product type, firm size, organizational type and unit area(dong) which were listed in statistics yearbooks, and the list of the owner's names, addresses, employee number, products and headquarters of firms which were listed in firm directories. Soft data were the results of the interviews with the 53 owners of firms surveyed among the firms selected by Proportional Stratified Sampling Method. The major findings were as follows: (1) Manufacturing location in Jangyu-Myun was regularized in 1980's in which decentralization of manufacturing was activiated. Though the industrialization of study area resulted from the birth, relocation and establishment of branches of the firms originated from the other regions, the relocation of small outer-oriented firms from the central city was the most important factor among them. (2) The main locational factors which induced the decentralizing manufacturing from the central city into Jangyu-Myun are closely related to land, transportation, personal factor, raw material suppliers and market. (3) The differences of important locational factors by the size and organizational type of firms are relevant to the characteristics of manufacturing location. (4) The changes of linkages attendant upon locational changes of firms were not so great and were localized in labor supply and marketing. (5) The strength of linkages is strong in the procurement of materials, in the subcontraction and in the marketing, but not in the ordering. (6) The main factors influencing on the formation of linkages are different by the types of linkages: monopolistic and oligopolistic supply are important in procurement linkages; characteristics of products and production capacity in the subcontraction and ordering; characteristics of products and the subsequent difficulties, in the marketing. (7) With the exception of procurement linkages, the strength of linkages with the outside of the study area are stronger than the linkages with the inside. The strength of linkages with the outside has distance-decay-function and strong linkages with the central city. (8) These spatial characteristics of linkages are different by products type, firm size and organizational type of firms: the spatial ranges of linkages are wider in the multi-location firms than in the single-location firms; the larger the firm size, the wider the spatial range of linkages: there is no consistent trend by products type. In conclusion, some facts described above were proved to be consistent with the results of proceeding studies in the other areas: influence of central city manufacturing relocation on industrialization in the suburb: different decentralization by products type, firm size and organizational types of firms: different locational factors by products type, firm size and organizational types of firms; linkage changes attendant upon locational changes of firms; spatial differences of linkages by products type, firm size and organizational type of firms. Some other factors were proved to be partly consistent: locational factors and spatial characteristics of linkages. Accordingly I think that the results of previous studies on the other areas can be applicable to the explanation of the location and linkage of manufacturing in Jangyu-Myun. For the better explanation on the characteristics of manufacturing decentralization from the central city, more empirical case studies on the location and linkage of manufacturing in the suburb areas are necessary.

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Development of Vibration Motor Using Coreless Permanent Magnet DC Motor (무철심 영구자석 직류 모터를 이용한 진동자 개발)

  • Hwang, Sang-Moon;Chung, Shi-Uk
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.7
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    • pp.15-23
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    • 1999
  • With a remarkable expansion of communication industry, a pager or a cellular phone becomes a necessary communication device in modern society. However, a paging signal by a buzzer is often acted as an unpleasant noise in some places, thus necessitating a paging signal by a vibration motor. In this paper, a simpler type of a vibration motor, a coreless permanent magnet(PM) DC motor, is considered to substitute for the conventional vibration motors. Using an analytical method, electromagnetic field and operating torque were calculated for the given inner and outer PM type motors, and the results were confirmed by FEM analysis. As design parameters, number of PM poles, PM radial thickness, coil arc angle and number of winding stacks were chosen for sensitivity analysis. It shows that coil arc angle is the most important design parameter to increase the motor performance, without giving an adverse effect on motor weight, size and manufacturing cost. Based on the analysis of the outer PM type motor, an outer square PM type motor is proposed as the final design. Compared to the outer PM type, outer square type provides more flexibility to attach to the small size cellular phones. With the optimum design of square outer PM DC motor, it can successfully substitute the conventional types with less expensive manufacturing cost. better performance and smaller necessary space.

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A Study on Class Loading in Java Virtual Machine (자바 가상 머신에서 클래스 로딩에 관한 연구)

  • 김기태;이갑래;유원희
    • The Journal of the Korea Contents Association
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    • v.3 no.2
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    • pp.39-45
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    • 2003
  • Dynamic dan loading and class linking of Java is a poweful mechanism. Many other system also support some form of dynamic loading and linking, but lazy loading, type-safe linkage, user-definable class loading policy, and multiple namespaces are important features of Java The ue U dan loading is assured of type safety. The security of Java greatly depends on type safety. In JVM, type safety mechanism is very difficult and access of accuracy is not dear, so type safety problems were raised. In paper, n analysis simple Java code and present a diagram graph and an operational semantics for dynamic class loading and type safety.

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Development of a Passive Knee Mechanism for Lower Extremity Exoskeleton Robot (근력 지원용 외골격 로봇을 위한 수동형 무릎 관절 메커니즘 개발)

  • Kim, Ho-Jun;Lim, Dong-Hwan;Han, Chang-Soo
    • The Journal of Korea Robotics Society
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    • v.12 no.2
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    • pp.107-115
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    • 2017
  • In this paper, four-bar linkage mechanism for the knee joint is developed which is used in prosthetics. But unlike the prosthetics, the feature of this mechanism is that the instantaneous center of rotation of the four-bar linkages can be moved behind the ground reaction force vector so that it can be passively supported without any external power. In addition, this mechanism is developed similar to the structure of the human knee joint for eliminating the sense of heterogeneity of the wearer. In order to design the mechanism with these two objectives, optimization design process is done using the PIAnO tool and detailed design is carried out through optimized variable values. The developed mechanism is attached to the robot which can assist the hip and ankle joints. In order to verify the operation of the developed knee mechanism, an insole type sensor was attached to the shoes to compare data values before and after wearing the robot. Result data showed that wearer wearing the exoskeleton robot with the knee mechanism was the same value regardless of whether the heavy tool is loaded or not.

An Experimental Study on the Measurement of the Instantaneous Surface Temperature of the Piston of the DI Mono Cylinder Diesel Engine (직분식 단기통 디젤기관 피스톤의 순간온도 측정에 관한 실험적 연구)

  • 이재순;이현구;강태경;이응래;정인곤;안병태
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.1
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    • pp.196-204
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    • 1998
  • For the experimental measurement of instantaneous surface temperature of the piston of the DI mono cylinder diesel engine, the instantaneous temperature proves, data acquisition system, and grass-hopper type linkage system were developed. The instantaneous temperatures on the piston bowl, crown, lands and skirt were measured and analyzed, and the following conclusions were derived ; (i) The crank angle for the maximum instantaneous temperature during one cycle varies and moves back and forth by the measuring positions and engine speeds. (ii) The engine speeds, the positions of the measuring points and the cooling water temperature had an effect on the instantaneous temperature amplitude. (iii) The instantaneous temperature suing phenomena appeared on the temperature profiles of the piston crown, top and second land of ring, but on the temperature profiles of the parts of the third land of the fing and skirt, they didn't appear, (iv) The isothermal lines in the piston were acquired through the operation of the finite elements method using the measured temperatures as the boundary conditions.

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Physicochemical Properties of Modified Rice Powder for Rice-Based Infant Foods III -Acetylated-coss linkage treatment on rice powder (반고형 이유식의 개발을 위한 변형 쌀가루 제조 및 이화학적 특성 III - 초산-처리 쌀가루)

  • Choi, Jung-Sun;Sohn, Kyung-Hee;Choi, Hee-Sun
    • Journal of the Korean Society of Food Culture
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    • v.12 no.5
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    • pp.469-475
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    • 1997
  • The modification of rice powder was attempted by treatment of acetic acid and epichlorohydrin to improve the functional properties of baby food. The initial gelatinization temperature of rice powder determined by amylograph was decreased from $79.5^{\circ}C$ to $63^{\circ}C$ by modification. The apparent and maxium viscosity of rice paste at $95^{\circ}C$ before and after modification were increased from 92B.U. to 236B.U. and from 100B.U. to 202B.U., respectively. The light transmittance of modified rice paste was increased from the temperature of $60^{\circ}C$ and by increasing the degree of substitution at the fixed temperature, while decrease more or less by the treatment of epichlorohydrin. The degree of retrogradation of the paste was decreased from 28.7 to 18.0 upon modification. The rate of syneresis of modified rice powder was decreased with increasing the drgree of substitution and ,the extend of epichlorohydrin treatment. Syneresis was not observed when acetylated rice powder whose DS value is 0.048 was treated with 0.25% of epichlorohydrin for the formation of cross-linkage. The addition of modified rice powder in preparation of semi-solid type infant food could improve the quality without lowering overall digestibility.

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Compensating algorithm for the secondary current of a measurement type CT considering the secondary voltage-core loss current curve and the flux linkage-magnetizing current curve (2차 전압-철손 전류 곡선과 자속-자화 전류 곡선을 고려한 측정용 변류기 2차 전류 보상 알고리즘)

  • Kang, Yong-Cheol;Zheng, Tai-Ying;Jang, Sung-Il;Kim, Yong-Gyun
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.65-66
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    • 2008
  • This paper proposes a compensating algorithm for the secondary current of the measurement current transformer (CT) that removes the effects of the hysteresis characteristics of the iron-core. The exciting current resulting from the hysteresis characteristics of the core causes an error between the primary current and the secondary current of the CT. The proposed algorithm decomposes the exciting current into the magnetizing current and the core loss current and each of them is estimated. The core loss current is calculated from the secondary voltage and the secondary voltage-core loss current curve. The core flux linkage is calculated and then inserted into the flux-current curve to estimate the magnetizing current. The exciting current at every sampling interval is obtained by summing the core-loss and magnetizing currents and then added to the measured current to compensate the secondary current. The performance of the proposed algorithm is validated under various conditions using EMTP generated data. The test results of the real CT were also included. The results indicate that the proposed algorithm can improve the accuracy of the measurement CT significantly, and thus reduce the size and the cost of the CT.

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