• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2648-2653
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• 2003

This paper describes the development of a 3-DOF laparoscopic assistant robot system with motor-controlled bending and zooming mechanisms using the voice command motion control and auto-tracking control. The system is designed with two major criteria: safety and adaptability. To satisfy the safety criteria we designed the robot with optimized range of motion. For adaptability, the robot is designed with compact size to minimize interference with the staffs in the operating room. The required external motions were replaced by the bending mechanism within the abdomen using flexible laparoscope. The zooming of the robot is achieved through in and out motion at the port where the laparoscope is inserted. The robot is attachable to the bedside using a conventional laparoscope holder with multiple DOF joints and is compact enough for hand-carry. The voice-controlled command input and auto-tracking control is expected to enhance the overall performance of the system while reducing the control load imposed on the surgeon during a laparoscopic surgery. The proposed system is expected to have sufficient safety features and an easy-to-use interface to enhance the overall performance of current laparoscopy.

• 한국항해학회지
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• 제25권2호
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• pp.97-106
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• 2001

이 연구는 항만교통정보센터의 시스템 확충 및 연안 선박교통관리제도의 도입에는 많은 비용이 소요되기 때문에 비용과 편익을 비교하여 타당성을 조사하고자 한다. 따라서 비용과 편익을 분석하는데 중요한 기초자료가 되는 사고예방효과를 추정하고자 한다. 추정의 방법은 거제해역에서 발생한 해양사고를 분석하여 원인요소를 도출한 후 이를 설문문항으로 구성하여 항만교통정보센터의 운영요원을 대상으로 설문을 실시한다. 연안 선박교통관리제도의 도입에 의한 사고예방효과는 충돌사고에서 55.572%, 좌초사고에서 51.667%로 추정되었다. 또한 인적요소와 환경요소에 의한 효과는 높지만 기술적 요소에 의한 효과는 미미한 것으로 분석되었다.

• 한국항해학회지
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• 제15권1호
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• pp.49-65
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• 1991

It is of great importance for any vessel under way, especially in rough sea, to be maneuvered safely with proper seakeeping performance. In this paper, the author aims to develope a navigational safety evaluation system in rough sea by analyzing ship's with the theory of wave spectrum using random process analysis and the theory of evaluating the seakeeping performance. The scope and the method of this study are as follows ; (1) Modelized typhoon mathematically to represent the sea condition in rough sea. (2) Estimated sea conditions by getting wave spectrum, supposing that the wave by typhoon is fully developed short crest irregular wave. (3) Defined evaluation factor of vessel's seakeeping performance and obtained response amplitude operators thereby. (4) Obtained the response spectrum of factors on seakeeping performance. (5) Defined and obtained evaluation index, dangerousness, relative and maximum dangerousness of factors on seakeeping performance. (6) Analyzed the calculated dangerousness of evaluation index and picked the vertical acceleration out of 7 factors as the presentative factor on seakeeping performance. (7) Carrid out the judgement of danger by obtaining dangerousness value according to steaming hour, course alteration and speed change. By synthesizing the above items, the authors suggests a computer model of navigational safety evaluation system and examined the validity of the model by computer simulation.

• 드라이브 ㆍ 컨트롤
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• 제12권2호
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• pp.39-48
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• 2015

In order to control the actuators of hydraulic machinery such as excavators, various control valves are typically assembled in a single block. Such a control block is called a main control valve(MCV). In this paper, we analyzed the working principle and the particular purpose of the design of all valves included in the MCV system. To Examine the reliability of the analysis model, the pressure drop of the MCV at each port was measured. The authors developed an analytical model of the control valve(main spool, load poppet, pressure relief, make up, and regeneration). The authors considered the notch shape of the spool while developing the analytical models of the main spool valve. Most importantly, at the stage before the analysis model was applied in the design tuning, the reliability was ensured by comparing the analysis results with the test results. This paper showed a process of developing an analysis model that can be utilized in the design and tuning stages.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.64-74
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• 2005

The effect of fuel injection spray on engine performance has been known as one of the major concerns for improving fuel economy and reducing emissions. In general, reducing the spray droplet size could prevent HC emission in gasoline engine. As far as PFI gasoline engine is concerned, the mixture of air and fuel may not be uniform under a certain condition, because breakup and production of spray droplets are made in a short distance between the fuel injector and intake valve. This study, by constituting PFI gasoline spray system, was performed to study the transient spray characteristics and dynamic behavior of droplets from two-holes two-sprays type injector used in DOHC gasoline engine. Mean droplet size and optical concentration in accordance with various conditions were measured by LDPA and CCD camera. Through this study, the variation of drop size and optical concentration could be used for understanding the behavior of unsteady spray was declared and the existing the small droplets between each pulse spray could be estimated caused to the development of wall film was conformed.

• 한국전기전자재료학회논문지
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• 제32권4호
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• pp.327-332
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• 2019

Recently, inverter control systems have attracted immense attention to increase the energy efficiency. However, such systems use repeated on/off high currents for linear operation control, instead of the prevalent step variable current control method. Hence, there arise concerns of personal and property damage, especially due to the durability, explosive characteristics, and operating speed of the fuse, which is responsible for safety and is one of the internal components using current control. Therefore, in this paper, we propose an IEC60127-4 SMD sub-miniature fuse, consisting of Ag-Cu alloys and ceramic powder for arc soothing. The IEC60127-4 SMD sub-miniature fuse has high durability and cut-off capacity, and operates safely in dangerous circumstances caused by the inverter control system.

• 한국항해학회지
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• 제17권1호
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• pp.37-48
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• 1993

When the vessel is running at the very low Froude numbers, the free-surface is difficult to be disturbed, wave-making is negligible, and the double -model velocity potential gives a very good approximation for calculating the velocity distribution just outside the boundary layer. If the speed of incident flow is gradually increased, the most perceptible change is the rise of the flow surface at stem. With further increase in speed, the nature of the flow at the bow changes completely, The flow ahead of the bow becomes more distrubed, the rise at the stem to stagnation height disappear, and the first wave crest, of less than the stagnation height, appears a small distance downstream from the stem. The present study is concerned with a small region of this flow, mainly in the bow region. The present investigation is primarily an experimental study of the flow in the bow region of s ship model, and it is undertaken in order to investigated systematically, the effect of bow geometry on this flow. The long-range objective is to use these results to guide the development of a mathematical model for predicting the flow about a ship's bow.

• International Journal of Concrete Structures and Materials
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• 제3권1호
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• pp.25-32
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• 2009

A non-destructive testing (NDT) method for evaluating physical properties of concrete including the compressive strength is highly desirable. This paper presents such an NDT method based on measurement of electromagnetic (EM) properties of the material. Experiments are carried out on cement mortar with different water/cement (W/C) ratios. Their EM properties including the conductivity and the dielectric constant are measured at different exposure conditions and curing periods over a wide frequency range of the EM wave. The compressive strength of these specimens is also tested. It is found that both the conductivity and the dielectric constant increase as the W/C ratio decreases and the curing period increases, which lead strength development in the specimens. A linear correlation is observed between the averaged EM properties over the 5 to 20 GHz frequency range and the measured compressive strength, demonstrating the effectiveness of the EM property-based NDT method in evaluating strength of OPC mortar.

• 식품보건융합연구
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• 제6권2호
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• pp.9-16
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• 2020

The global halal market is forecast to grow at an annual average of 5.2 percent from 2017 to $3.07 trillion in 2023 due to the high growth rate of the world's Muslim population, the spread of halal-certified food consumption and the economic growth of the Muslim world. Through this study, the difficulty of obtaining halal certification can be overcome through accurate understanding of the general supply chain and other halal supply chain. Also, by examining the trends and requirements of halal logistics standards in countries with advanced halal logistics systems, halal logistics certification agencies, and halal port logistics, we can help establish our own halal logistics system by finding areas that can be benchmarked in Korea and differentiated from those that can be found. For the safe supply chain management of halal products between logistics Supply Chain, an integrated logistics system shall be developed to manage customs and customs as one-stop, while maintaining a complete halal condition on a series of logistics processes such as storage, transportation, customs clearance, etc. Korea, entry into the halal logistics market through halal integrity guarantee solution or platform development can also be considered, taking advantage of the strength of IT and packaging.

• Elastomers and Composites
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• 제54권1호
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• pp.70-76
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• 2019

The function and purpose of the marine rubber fender, to prevent the damage of the ship and the mooring while the ship is being attached to the pier. However, maintenance of the fender after installation is not enough, because it is generally handled as an attachment facility. Estimation the life of a marine rubber fender is important in the maintenance of a port. When manufacturers design and produce marine rubber fenders, they do so according to various conditions such as the reaction force acting on the hull and docking vessel and deformation after absorbing the kinetic energy of the ship. In this study, a method for predicting and evaluating service life from the product design and development stage was established, in order to evaluate the durability of the marine rubber fenders. The SSp-300H and HSP-300H models were used to predict the service life. The method developed in this study, is expected to predict the service life of the marine rubber fender accurately and in a comparatively shorter time, thereby contributing to the evaluation standard and quality stability of the product.