• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.7
• /
• pp.965-971
• /
• 2017

The primary objective of this study was to assess the energy efficiency performance of an optimized hull form capable of saving energy based on existing vessels. The bow shape of existing vessels was investigated, giving consideration to design draft and speed. Resistance performances were also assessed for existing vessels according to operating conditions. Commercial CFD codes and model test materials were used to assess effective power. An optimized hull form with minimum resistance was selected given real operating conditions. The effective horsepower of existing and optimized vessels was estimated at three speeds. Resistance performance for an optimized vessel showed a 6 % improvement in effective horsepower at design speed (12 knots) compared to existing vessels. Quasi-propulsive efficiency employed experimental data, while energy efficiency performance was analyzed based on operating days, bunker fuel oil C cost, daily fuel oil consumption and specific fuel oil consumption. Energy efficiency performance for an optimized vessel showed a gain of 30 million won per year in reduced costs at design speed (12 knots) compared to existing vessels.

• Journal of Korea Water Resources Association
• /
• v.47 no.5
• /
• pp.483-490
• /
• 2014

The design procedures for a biological reactor and a secondary settling tank (SST) of an activated sludge system are based on the steady state design method (Ekama et al., 1986; WRC, 1984) and the 1-D flux theory design method (Ekama et al., 1997), respectively. This study combined both of the design procedures, to determine the optimum sludge concentration in the reactor and the best design with the lowest cost. The best design of the reactor volume and the SST diameter at the optimum sludge concentration were specified with varying wastewater and sludge characteristics, temperature, sludge retention time (SRT) and peak flow rate. The effects of the influent wastewater characteristics, such as substrate concentration and unbiodegradable particulate fraction, were found to be considerable, but the effect of unbiodegradable soluble fraction was to be negligible. The effects of sludge settling characteristics, were also significant. SRT, as an operating parameter, was found to be an important factor for determining the optimum sludge concentration. However, the effect of temperature was found to be small. Furthermore, for designing a large scale wastewater treatment plant, the number of reactors or SSTs could be estimated, by dividing the total reactor volume or SST area. The new combined design procedure, proposed in this research, will be able to allow engineers to provide the best design of an activated sludge system with the lowest cost.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.4
• /
• pp.935-942
• /
• 2011

This study aims to design and implement the finger gesture recognizing system that automatically recognizes finger gestures input through a camera and controls the computer. Common CCD cameras were redesigned as infrared light cameras to acquire the images. The recorded images go through the pre-process to find the hand features, the finger gestures are read accordingly, and an event takes place for the follow-up mouse controlling and presentation, and finally the way to control computers is suggested. The finger gesture recognizing system presented in this study has been verified as the next-generation interface to replace the mouse and keyboard for the future information-based units.

• Fire Science and Engineering
• /
• v.12 no.4
• /
• pp.59-69
• /
• 1998

As high-rise Apartment buildings increase the importance of fire prevention and escape performance. While these buildings provide dwellers with much more houses, they have the basic escape safety problem in their apartment buildings. In these respect, this study aims to present the Principles of Fire protection for the escape performance of apartment buildings. This study reviews basic theories of escape in apartment buildings. I figure out the characteristics of the fires in apartment buildings by case studying the fire in the apartment buildings, and find out the existing problems for escape performance and fire prevention by surveying. In this study, the major findings are as follows: The planning method should be based on the escape performance. In the planning stage, fire safety should be considered more seriously than law and economic factors.

• Journal of Power System Engineering
• /
• v.16 no.5
• /
• pp.5-12
• /
• 2012

희박예혼합기의 급속연소에 관한 연구를 위하여 2-실린더 가솔린 엔진을 부실 타입의 압축천연가스(CNG) 분사 엔진으로 개조하였다. 본 연구에서는 부실의 최적설계에 관심을 두고 두 종류의 부실을 적용하여 실험을 실시하였고, 부실의 체적과 홀 개수는 1.5cc와 6개로 각각 동일하게 하고, 홀 직경을 0.8mm 및 1.1mm로 달리하였다. CNG연료는 포트연료분사(Port fuel injection; PFI)와 부실분사(Sub-chamber injection; SCI)에 의해 엔진에 독립적으로 공급되고, 그 실험결과로 구한 연소압력, 평균유효압력(IMEP), 질량연소분율과 사이클변동계수(COV) 등을 서로 비교하였다. 본 연구의 대표적 실험연구결과로서 PFI 타입의 엔진연소특성은 희박예혼합기의 경우를 제외하고 모든 조건에 있어서 기존의 가솔린 엔진과 비슷하였고, SCI 타입의 엔진연소특성으로 평균유효압력은 부실 내에 불완전 예혼합기형성으로 PFI 타입보다 낮았으며, COV는 SCI 타입이 희박가연한계가 확대됨으로 인하여, 특히 높은 공기과잉률 범위에서 PFI 타입과 비교해 보다 좋은 결과를 나타내었다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.3 no.1
• /
• pp.10-19
• /
• 2002

The purpose of this paper is to describe the design of a general multipurpose batch process or plant in terms of a series of mathematical programing models, and to develop approach solution methodologies. The proposed model for a single period is based on the formulation (MINLP; Mixed Integer Nonlinear Programming) of Papageorgaki and Reklaitis [1], but was linearized (MILP; Mixed Integer Linear Programming) so as to obtain an exact and practical solution, and to allow treatment of uncertainties to be considered in expanding the plant. As a solution strategy a modified Benders' Decomposition was introduced and was tested on three example problems. The optimizing solver, OSL code provided by the IBM Corporation, was used for solving the problems. The solution method was successful in that it showed remarkable reduction in the computing times as compared with the direct solution method.

• The KIPS Transactions:PartB
• /
• v.14B no.6
• /
• pp.437-444
• /
• 2007

The objective of this paper is to accommodate the existing motion-capture-based animation to small memories and low computing powers of mobile embedded systems. To use efficiently memories, we propose a paradigm in which a motion capture database is compressed on a PC and so-compressed motion capture database is decompressed little by little on mobile embedded systems and the decompressed data are eliminated right after used. As a compression method for this paradigm we propose an approach that compresses captured motion rendering parameters using a polynomial function fitting method. To enhance its performance we also propose an optimization method for the degree of the polynomial fitting function. Using so-obtained compression method we demonstrate motion-capture-based animation on commercial mobile embedded systems.

• Journal of the Korean Institute of Gas
• /
• v.23 no.1
• /
• pp.19-26
• /
• 2019

In this study, we developed a cooling system for 1 ton size refrigeration vehicle using carbon dioxide natural refrigerant among hydrocarbon type refrigerant which is attracting attention as environment friendly refrigerant, and designed a heat exchanger and a unit cooler to raise COP. In addition, existing CNG 5 ton refrigerated trucks were converted into LNG vehicles to increase the efficiency of the cooling system and ensure safety against CNG. As a result, environmentally friendly refrigerated trucks using natural refrigerants of 1 ton and 5 ton sizes were developed.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.3
• /
• pp.73-79
• /
• 2021

In the wave of the 4th industrial revolution, smart factory is required in many factories. However, small and mid-sized companies (SMEs) still have aging machines and are having difficulties in the data collection stage, which is the basis of smart factories. This study proposes a low cost monitoring method by using an open source based technology that extracts data from the image of the facility control panel without the need for modification of existing facilities. The proposed method was tested and evaluated for forging facilities in automobile parts manufacturing plants through prototyping. As a result of the evaluation, it was confirmed that low-cost facility monitoring is possible, and it will help SMEs build smart factories.

• Journal of IKEEE
• /
• v.26 no.4
• /
• pp.560-567
• /
• 2022

This paper proposed an application of agile management method to resolve the electrical system issues identified during the mass production phase of aged aircraft performance improvement. The proposed method was applied from issue analysis to on-site verification and testing stage, before the formal configuration control process. At this time, the project was carried out by setting a sprint period to complete the verification according to requirements through daily scrum and sprint review. As a result, It was verified that the wiring installation of the aircraft, which was the output of the sprint, met requirements within the defined sprint period.