• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.1
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• pp.66-73
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• 2017

This study attempted to design lights with Type II distribution suitable for LED street lights based on the regulations of street light distribution developed by the Illuminating Engineering Society of North America (IESNA). The shape of an asymmetric lens, different from that of a rotationally symmetric lens, cannot be generated using a simple mathematical formula. In the first trial, the outline of the lens was fixed and simulated to confirm the distribution type. Following ISENA regulations, some problems that occurred during simulations and repeating was be modified that process is how we detected errors. Through optical research and simulations, a lens conforming to the regulations of Type II very short, Type II short, and Type II medium distributions was developed. A prototype was developed using simulation data and it was subjected to distribution tests. The results show that it can compare with property of Type II distribution.

• KIISE Transactions on Computing Practices
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• v.21 no.11
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• pp.739-744
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• 2015

In this paper, we examine the project-based educational practice that is co-developing a solution to the local food inventory management system. This project is aimed at the practical business of IT distribution in small and medium industries, and is linked with the project course on undergraduate students of IT division. For the practical project of the IT distribution in small and medium industries, an employee in charge of the project participates as a mentor such that he presents the project subject and the students develop the system for the subject. This system emerges from existing theory and the necessity for a term project, and this course leads students to learn practical knowledge through discussion with the employee in charge. Through this course, the latest technology is shared mutually, and students have the opportunity to understand a domain of the IT distribution business. As students experience how to understand and solve cost, quality and delivery time for the project by themselves, they build confidence. Also, the company can save on costs for the development of prototypes, while creating an opportunity for students to experience working with seasoned staff.

• Journal of Korean Society for Atmospheric Environment
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• v.1 no.1
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• pp.93-98
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• 1985

Mass size distribution of atmospheric particulates were measured using an Andersen using an Andersen sampler in urban air. The atmospheric particulates were fractionated in eight stages of an Andersen sampler operating at 28.4$\ell/min$ and collected on polyester sheets. A quartz filter was placed behind the last stage collect permeated partculates. The size distribution of atmospheric particulates were divided around 1-2 $\mu$m into two groups, coarse and fine particulates regardless of sampling times. The variation of course particulates concentration was higher than fine particulates among sampling times. Different meterorological conditions and natural phenomena brought high variation of course particulates' concentration. The rain caused removal of coarse particulates seriously and the yellow and may take part in a increase of the course particulates in spring. The average concentration of atmospheric particulates to be collected by Andersen sampler was 170.8 $\mug/m^3$ during 3 times of sampling. Among them the average concentration of atmospheric particulates which could penetrated under a bronchi and alveoli were 70.4$\mug/m^3$ and 36.6$\mug/m^3$ respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.371-377
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• 2017

In this study, the heat dissipation performances of metal printed circuit boards (MPCBs) and flexible printed circuit boards (FPCBs) used in light-emitting diode (LED) lights were compared and analyzed by performing a heat dissipation simulation using a thermal flow analysis program. The results were summarized graphically. The temperature distribution of the MPCB was found to be better than that of the FPCB, indicating the better heat dissipation performance of the MPCB. For the two FPCB structures studied, we confirmed the LED temperature and temperature distribution by thermal flow analysis and found that for better overall heat dissipation performance, PCBs should preferably have an asymmetric structure. We confirmed the possibility of using FPCBs, which are characterized by a flexible structure, for LED lighting.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.4
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• pp.448-454
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• 2015

In this paper, the band structural design that is typically in a line was arranged in a ring shape, so as to configure the high power LED lighting in such a way as to form a concentrated light distribution angle of less than 15 degrees. The parabolic aluminized reflector PAR38 that facilitates design using area and the area of the optical system to the same extent, applied a multiple light-source condenser lens optical system for the control of integration. The LED used here implemented a single linear light source using ans LED module with ans LED, flip-chip chip-scale package. The optical system was designed based on the energy star standard.

• Culinary science and hospitality research
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• v.6 no.1
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• pp.253-274
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• 2000

This report deals with what the distribution industry is and the actual condition and keynote of the domestic distribution industry. Now, it is difficult compare with the domestic distribution industryand other advanced nation. because of inferior enviroment and given circumstance such as. Open market pressure. We will study about realities and weakness of the domestic distribution industry, also check how to cope with, especially the Government and enterprise, these difficulties for the development of the domestic distribution industry.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.6
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• pp.609-617
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• 2014

We have studied a chip-on-board LED lighting optical system for various luminous-intensity-distribution angles of the LED. An optical system that can accept different LEDs was made to reduce the systems's weight and size as we selected the chip-on-board LED, which is easy to apply to optical systems, unlike existing package-on-board LEDs. The luminous-intensity-distribution angles were $45^{\circ}$, $60^{\circ}$, $90^{\circ}$, and $120^{\circ}$. We researched these four types of optical systems. The $45^{\circ}$ and $60^{\circ}$ units were developed into reflectors, and the $90^{\circ}$ and $120^{\circ}$ units, into lenses. We checked the performance of the designed optical system through simulation and made a mock-up. Then we made a prototype of the chip-on-board LED high bay for use with the mock-up. After measuring its performance, we tested the luminous-intensity-distribution angles and compared them with simulation data. The resulting prototype was developed considering brightness, light uniformity, age, and economics which are suitable for a factory environment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.2
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• pp.193-199
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• 2013

Course keeping ability of ships under wave are analyzed with wave. The simulation with three degrees of freedom is developed and 3-D source distribution method is applied to get wave force for the simulation. The simulation is conducted with the restriction of maximum rudder angle and time delay of control and regular wave and irregular wave are considered as the source of external forces. Simulations with ships which have different maneuverability with tuned hydrodynamic coefficients are developed to assess the variation of the course keeping ability depending on the ship's maneuvering characteristics. The course Keeping ability is evaluated by comparison of distance while the ships are simulated with autopilot control.

• Journal of Distribution Science
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• v.18 no.4
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• pp.73-78
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• 2020

Purpose: This study was to examine public access defibrillator (PAD) deployment on some golf courses and to analyze automatic external defibrillators (AEDs) demand by appropriate distance. Research design, data, and methodology: We conducted telephone interview on 124 golf courses in Gyeonggi and Gangwon province in South Korea. The area within 3 minutes by 3 minutes for retrieval and 1 minute for shock and 1.5 minutes by the American Heart Association (AHA)recommendation for community AED placement were calculated as 3.14×162㎡ and 3.14×100㎡. Results: The average area was 1,811,481.8㎡, and 29 (42.7%) in below 999,999㎡, 75 (60.5%) in 1,000,000 to 1,999,999㎡, 12 (9.7%) in 2,000,000 to 2,999,999㎡ took up. The average retrieval time was 161.8 seconds, and 5 (4.1%) in below 90 seconds, 10 (8.0%) in 91 to 180 seconds took up a small part. AED demands according to 3 and 1.5 retrieval minutes were 2,602 and 6,986 respectively. Average AED demands per golf course were 21.0 and 56.3 respectively on 124 golf courses. Conclusions: The numbers of AED needed in South Korean golf course were 5,880 to 15,764. To ensure defibrillation on the golf courses, the supply and distribution of AEDs should be strengthened.

• Journal of Engineering Education Research
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• v.10 no.1
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• pp.5-19
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• 2007

A general education course is different from a major course in an engineering college. Therefore, they influence a learning outcomes according to their forms and contents. In particular, an engineering college in korea is open to argument against a general education course. Because a general education course has to observe the criterion of ABEEK. Consequently, the purpose of this study is to compare general education courses of engineering colleges in USA. For it, this study analyzes the completion method and academic area of a general education course. In result, this study suggests the property and implication of a general education course in an engineering college.