• Title/Summary/Keyword: Engine Cases

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A Study on Tax Ontology Construction (조세 온톨로지 구축에 관한 연구)

  • Chang, Inho
    • Journal of Korean Library and Information Science Society
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    • v.44 no.1
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    • pp.385-408
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    • 2013
  • The purpose of this study is to build the tax ontology which can be used to manage imposables by the state or local governments. In this, the tax and related concepts were analyzed and then concept hierarchy i.e., taxonomies were formed. Especially, in the concept hierarchy, after multiple inherits were decomposed as 'primitive concepts' and then Rector's 'methodology of ontology implementation normalization', in which defined concepts were recombined, was used. The methodology employed was that the tax system, which was entangled with the direct taxes, local taxes, and property taxes that has multiple-inherits, was expressed explicitly and logically. After that, automatic classification was carried out through the inference engine, consistency was verified. Finally, some practical cases of ontology created were enumerated.

A study on Policy Direction for Restructuring of Korean Fisheries-Case Analysis of Selected Countries (어업구조조정 정책 방향에 관한 연구-외국사례 연구를 통한 분석)

  • Chae, Dong-Ryul
    • The Journal of Fisheries Business Administration
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    • v.41 no.1
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    • pp.129-156
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    • 2010
  • Well-deviced buyback programs may be detrimental to achieve sustainable fisheries. However, it is not difficult to find undesirable examples that the result of buyback program have no impact on fish stocks or the sustainability of the fishery. This paper discusses the problems and policy directions for successful restructuring of Korean marine fisheries through comparative analysis of selected cases from five main countries including Japan, Norway, Italy, Taiwan and Australia. From the analysis, this study demonstrated that Korean buyback program just pursue the reduction of boat number but passed over alleviation of the real ability in fishing industry. Although there were clear decrease of fishing effort in a certain parts of fisheries and some evidences of advancement in efficiency, it seemed hard to continue these effects because the Korean policy lacks consistency and coherence of systematic restructuring. To summary, four things are recommended for successful application of Korean buyback program; first is to establish the obvious goal of the program, second is to introduce downsizing in both fleet capacity and engine power, third is to conduct other management tools simultaneously to help resource restoration, and last, but not the least is to induce voluntary participation of fishermen providing opportunity to pursue their mutual interest.

Studies on Coupled Vibrations of Diesel Engine Propulsion Shafting(2nd Report: Analyzing of Forced Vibration with Damping) (디젤기관 추진축계의 연성진공에 관한 연구(제2보 : 강제 감쇠 연성진동해석))

  • 전효중;이돈출;김의간;김정렬
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.3
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    • pp.563-572
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    • 2001
  • With the results of calculation for natural frequencies the reponses of forced coupled vibration of propulsion shafting system were investigated by the modal analysis method. For the forced vibration response analysis, the axial exciting forces, the axial damper/detuner, propeller exciting forces and damping coefficients were extensively considered. As the conclusion of this study, some items are cleared as follows.-The torsional vibration amplitudes are not influenced by the radial excitation forces of the crank shaft. -The axial vibration amplitudes are influenced by the tangential exciting forces as well as the radial exciting forces of the crank shaft. The increase of the amplitudes is observed in the speed range at the neighbourhood of any torsional critical speed. 1The closer the torsional and axial critical speed. the larger coupling effect becomes. -The axial exciting force of propeller is relatively strong comparing with axial exciting forces of cylinder gas pressure and oscillating inertia of reciprocating mechanism. Therefore, the following conclusions are obtained. -Torsional vibration calculation with the classical one dimensional model is still valid. -The influence of torsional excitation at each crank upon the axial vibration is improtant. especially in the neighbourhood of a torsional critical speed. That means that the calculation of axial vibration with the classical one dimensional model is inaccurate in most of cases.

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Computational Study on The Effect of Injection Nozzle Hole Exit Angle Variation on Injection Characteristics (분사노즐 출구 각도 변화가 분사특성에 미치는 영향에 관한 계산적 고찰)

  • Kim, Ju Youn;Park, Kweon Ha;Lee, Seung Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.36 no.8
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    • pp.997-1002
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    • 2012
  • Emission regulations have been strengthened step by step for marine engines. A noble measure is required both inside and outside of the combustion chamber. The combustion characteristics in cylinder have a very close relationship with the exhaust emission characteristics. Injection valve and nozzle hole geometry is an important factor for combustion. The study to improve the spray characteristics has concentrated on nozzle inlet geometry and nozzle hole diameter, but the exit geometry has not considered. In this study the nozzle exit angle variation was tested. The results show that the angle between $30^{\circ}$ and $60^{\circ}$ is more effective than the other cases.

Study of Vibration on Residential Area Near by Railroad (철도주변에 위치한 주거지역의 진동에 관한 연구)

  • 정선호;최형일
    • Journal of KSNVE
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    • v.7 no.1
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    • pp.117-125
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    • 1997
  • The aim of this research is to measure the damage caused by the vibrations of passing trains. In order to determine the vibration levels of the trains, twelve points along the Honam, Cholla and Kyungjun lines were chose. There are two goals to be achieved from the data gathered. The first is to determine whether or not the trains are operating under governmentally determined levels. The second goal is to establish countermeasure in order to minimize the effects of the vibrations on the people who live near the train lines. A vibration level meter was used to measure the vibration levels at all twelve points at times when no trains were travelling and at times when trains were travelling. As a result, it was found that Saemaeulho and Mugunghwaho, had a higher vibration level of 2 - 3 dB than Pidulgiho and freight trans. There were no relationship between speed and vibration level. The vibration levels did change according to capacity and size of the engine. In such cases there was a difference of 2 - 7 dB. Where vibration proof ditches were in place, the vibration level were decreased by 3 - 6 dB. The practical decreases in vibration levels was similar to the theoretical decreases.

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Development of Remote Vehicle Information Storage System Using Wireless Communication (무선통신을 이용한 원격 차량운행정보 저장시스템 개발)

  • 이중현;고국원;최병욱;고경철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.576-579
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    • 2004
  • Recently, using GPS and equipment that recognizes the position of the car such a computer system inside the car are very universalized. Specially, the technique that diagnoses troubles and prevents troubles through scanning engine ECU is very popularized also. However, because these data have to be directly transferred and received from the car, in cases of traffic accident such as serious damage or car theft, it is impossible to receive the data at the time of accident. In order to receive and preserve the data safely regardless of these situations, it is possible to provide data for analyzing reasons of accident and prevent accidents from occurring by using wireless communication to receive the transferred information of the car, then saving into a Database system DB, or grasping the situation of the car and the driving pattern of drivers through analyzing stored data. Moreover, due to developing some related services such as providing the information about the real time of the accident, diagnoses of the car and alarms, etc. It is expected to contribute to creating added values.

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An Analysis on U-health Business Models: Focused on the Changes of Life Insurance Industry (유헬스 비즈니스 모델 분석 : 생명보험 산업의 변화를 중심으로)

  • Cho, Dong-Hwan;Kim, Seong-Ho
    • The Journal of the Korea Contents Association
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    • v.10 no.8
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    • pp.381-390
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    • 2010
  • Recently major developed countries such as U.S. and EU selected u-health as future growth engine industry, and concentrated their capabilities. Major companies all around the world entered this u-health business, too. Most of the research in this field have confined their research focus on the elementary technologies for infrastructure building. This research systematically investigates u-health business models with various objectives in various sub-fields. For this purpose, the value chain of u-health industry is analyzed, and then various business model cases are explored all around the world. Finally, the future changes possible to occur in the life insurance industries are analyzed.

Durability Improvement of Engine Bulkhead by Adjusting Design Parameters (설계인자변화에 따른 엔진 벌크헤드 내구성 향상)

  • Yang, Chull-Ho;Han, Moon-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.2
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    • pp.111-116
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    • 2011
  • Three-dimensional finite element analyses have been performed to improve the durability of bulkhead. To keep pace with design changes and concentrate on regions of interest, SUBMODEL technique in ABAQUS was used for analysis. An analysis was conducted with following load cases: 1) Cap press-fit, 2) Bearing crush, 3) Bolt assembly, 4) Hot assembly, 5) Firing load, 6) Alternating firing load, 7) 2nd hot assembly. Fatigue analysis was done using commercial software FEMFAT and fatigue factors at the interested regions such as bolt tip area, counter bore, breathing hole, honing clearance were calculated and compared to aid design validation. Finite element modeling in the area of thread engagement used a simple constraint equations. Increasing bolt length, to a minimum of 39 mm above joint face gives a better fatigue resistance to the bulkhead. Breathing hole helps not only circulate the air in the crankcase but also fatigue resistance of bulkhead by relieving the stress at the critical locations.

A Numerical Study of Blade Sweep Effect in Supersonic Turbine Rotor (초음속 터빈의 로터 블레이드 스윕 효과에 대한 수치적 연구)

  • Jeong, Soo-In;Jeong, Eun-Hwan;Kim, Kui-Soon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.830-834
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    • 2011
  • In this study, we performed three-dimensional CFD analysis to investigate the effect of the rotor blade sweep of a partial admission supersonic turbine on the stage performance and the flow field. The computations are conducted for three different sweep cases, No sweep(NSW), Backward sweep(BSW), and Forward sweep(FSW), using flow analysis program, $FLUENT^{TM}$ 6.3 Parallel. The results show that BSW model give the effect on the reducing of mass flow rates of tip leakage and the increasing of t-to-s efficiency.

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Combustion Dynamics of a Gas Generator Assembled with a Turbine Manifold (터빈 결합 환경의 가스발생기 동적 연소 특성)

  • Seo, Seong-Hyeon;Lim, Byung-Jik;Ahn, Kyu-Bok;Lee, Kwang-Jin;Kim, Jong-Gyu;Han, Yeoung-Min;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.05a
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    • pp.121-124
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    • 2008
  • This paper presents experimental results of dynamic characteristics of fuel-rich gas generators. Pressure fluctuation measurements in the chamber and manifolds have been analyzed. Gas-generator-alone tests revealed stable combustion regardless of a chamber pressure but low-frequency combustion instabilities occurred for cases of turbine-manifold tests at chamber pressure conditions below 50 bar. The instabilities are considered as an axial resonant mode and acoustic intensity increases along with a chamber pressure.

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