• 패션비즈니스
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• 제19권4호
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• pp.92-108
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• 2015

This study aimed at developing a down jacket prototype that utilized sunlight as an alternative energy source with no air pollution. The jacket is filled with flexible solar panels and has a heat-generating function and LED function. In this study, three smart down jacket prototypes were developed, and the jacket's capabilities were demonstrated through the thermal effect on the performance test. The typical output voltage of the flexible solar panels was 6.4V. By connecting the 2 solar cell modules in series, the final output voltage was 12.8V. A battery charge regulator module was used the KA 7809 (TO-220) of 9V. Three heating pads were to be inserted into the belly of the jacket as direct thermal heating elements, and the LED module was configured, separated by a flash and an indicator. The smart down jacket was designed to prevent damage to the down pack without the individual devices' interfering with the human body's motion. Because this study provides insulation from extreme cold with a purpose, the jacket was tested for heat insulation properties of non-heating, heating on the back, heating on the abdomen, and heating on both the back and abdomen in a sitting posture in a static state. Thermal property analysis results from examining the average skin temperature, core temperature, and the temperature and humidity within clothing showed, that placing a heating element in one place was more effective than distributing the heating elements in different locations. Heating on the back was the most effective for maintaining optimal skin temperature, core temperature, and humidity, whereas heating on the abdomen was not effective for maintaining optimal skin temperature, core temperature, or humidity within clothing because of the gap between the jacket and the body.

• Design & Manufacturing
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• 제14권3호
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• pp.23-30
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• 2020

Laser Assisted Thermo-Compression Bonding (LATCB) has been proposed to improve the "chip tilt due to the difference in solder bump height" that occurs during the conventional semiconductor chip bonding process. The bonding module of the LATCB system has used a piezoelectric actuator to control the inclination of the compression jig on a micro scale, and the piezoelectric actuator has been directly coupled to the compression jig to minimize the assembly tolerance of the compression jig. However, this structure generates a lateral force in the piezoelectric actuator when the compression jig is tilted, and the stacked piezoelectric element vulnerable to the lateral force has a risk of failure. In this paper, the optimal design of the flexure hinge was performed to minimize the lateral force generated in the piezoelectric actuator when the compression jig is tilted by using the displacement difference of the piezoelectric actuator in the bonding module for LATCB. The design variables of the flexure hinge were defined as the hinge height, the minimum diameter, and the notch radius. And the effect of the change of each variable on the stress generated in the flexible hinge and the lateral force acting on the piezoelectric actuator was analyzed. Also, optimization was carried out using commercial structural analysis software. As a result, when the displacement difference between the piezoelectric actuators is the maximum (90um), the maximum stress generated in the flexible hinge is 11.5% of the elastic limit of the hinge material, and the lateral force acting on the piezoelectric actuator is less than 1N.

• 한국항행학회논문지
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• 제27권5호
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• pp.610-620
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• 2023

4차 산업 혁명에 기반한 기술발전 및 항공사들의 고객 유치를 위한 경쟁으로 인해 항공기 인테리어 시장에 대한 관심이 증가하고 있으며, 그 일환으로 국내에서는 FAA Part.25급 민항기를 대상으로 한 CDS (Cabin Display System)이 개발되고 있다. CDS는 IDPM (Integrated Display Processing Module)로 제어되는 대형 Flexible 및 투명 OLED (Organic Light Emitting Diodes)를 활용하여 승객들에게 다양한 멀티미디어 서비스를 제공하는 시스템으로 고품질의 서비스 제공을 위해 대용량의 미디어 콘텐츠 활용이 필수적으로 요구된다. 본 논문에서는 대용량 파일들의 효율적인 Data Load Process를 수행하기 위한 새로운 방안을 제시하고 그 구현 및 성능을 다룬다. 본 연구 결과는 기존 ARINC-615A 대비 Data Load Process 개발 비용의 절감과 더불어 신뢰성 높은 대용량 파일 전송이 필요한 항공 장비의 Data Load Process 개발에 대체 적용이 가능할 것으로 기대된다.

• 한국융합학회논문지
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• 제8권12호
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• pp.15-22
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• 2017

본 논문은 ICT 융합 산업인 스마트 공장, 스마트 그리드, 스마트 홈, 스마트 교통, 스마트 헬스 케어 등의 분야에서 사용되는 서비스 기반 프로토콜들의 취약점을 분석하여 보안 위협을 도출하고 이를 탐지 및 차단할 수 있는 기술들을 제안하였다. 또한 프로토콜 공통의 보안 요소를 정의하고 해당 요소를 포함한 프로토콜 계층별 보안 모듈을 설계하여 개방형 환경에서 쉽고 빠르게 보안 기능을 개발할 수 있도록 하는 서비스 지향 프로토콜 보안 프레임워크를 설계하였다. 서비스 프로토콜 독립적인 보안 모듈과 특화된 보안 모듈을 분리한 프레임워크 구조로 개발하여 다양한 프로토콜이 사용되는 ICT 융합 산업 환경에서 유연하고 신속한 융합 보안 시스템 개발이 가능해 질것이다. 더불어 운영 중인 시스템에 필요한 보안 모듈을 탑재하여 ICT 서비스 네트워크의 전반적인 보안 수준을 향상시키고 보안 모듈별 재사용이 가능하여 산업 보안 분야에 생산성이 향상될 것이다.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1471-1481
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• 2014

This paper presents the new power dissipation model of individual switching device in a high-level modular multilevel converter (MMC), which can be mostly used in voltage sourced converter (VSC) based high-voltage direct current (HVDC) system and flexible AC transmission system (FACTS). Also, the voltage balancing method based on sorting algorithm is newly proposed to advance the MMC functionalities by effectively adjusting switching variations of the sub-module (SM). The proposed power dissipation model does not fully calculate the average power dissipation for numerous switching devices in an arm module. Instead, it estimates the power dissipation of every switching element based on the inherent operational principle of SM in MMC. In other words, the power dissipation is computed in every single switching event by using the polynomial curve fitting model with minimum computational efforts and high accuracy, which are required to manage the large number of SMs. After estimating the value of power dissipation, the thermal condition of every switching element is considered in the case of external disturbance. Then, the arm modeling for high-level MMC and its control scheme is implemented with the electromagnetic transient simulation program. Finally, the case study for applying to the MMC based HVDC system is carried out to select the appropriate insulated-gate bipolar transistor (IGBT) module in a steady-state, as well as to estimate the proper thermal condition of every switching element in a transient state.

• 한국재난정보학회 논문집
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• 제14권1호
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• pp.28-35
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• 2018

본 연구에서는 재난현장 또는 일상에서 발생할 수 있는 다수사상자의 중증도 분류를 신속하고 정확하게 수행하기 위한 시스템을 설계하여 구현하였으며, 중증도 분류 알고리즘의 정확도뿐만 아니라 사용자 편의성 등 현장의 요구사항을 적극 반영하였다. 개발된 e-Triage System은 IoT개념을 활용하여 다양한 중증도 분류 알고리즘을 적용하였으며, 기존의 중증도 분류표의 단점을 극복하기 위하여 NFC 모듈 등 전자적 요소를 반영한 e-Triage Tag를 구현하였다. 앱으로 구현된 중증도 분류 알고리즘을 사용하여 신속하고 정확한 환자의 평가가 가능함을 입증하였고, 시인성을 위해 전자 중증도 분류 결과를 4가지 LED램프로 표출하였으며, 2차 분류를 통해 RTS 점수를 FND(Flexible Numeric Display)로 표출하였다.

• Tribology and Lubricants
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• 제16권1호
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• pp.39-45
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• 2000

In this paper, the effects of shaft and bearing flexibilities are investigated for the accurate modeling of a shaft-bearing system supported by ball bearings. Generally, rolling bearings are modeled by simple rigid pin-joint in the mechanical design. However, they can no longer be modeled by ideal boundary conditions in the advanced applications because the rigid pin-joint model cannot satisfy the current trends of mechanical design decreasing mass and reducing volume. Consequently the flexible support model of ball bearing is investigated using the static analysis module developed by A .B. Jones and T. A. Harris. A simple two-bearing system, supported by two deep groove ball bearings and radially loaded on the shaft midway between the bearings, is utilized to validate the coupled model of shaft-bearing system. Numerical computations using the model indicate that the shaft span length, locating/floating bearing arrangements and applied bearing size are significant factors in determining the mechanical behaviors. The flexible support model of ball bearing can be escaped to over-estimate in the bearing fatigue life. The proposed simple design formulation obtained by numerical simulations can approximately predict a rate of bearing life reduction as a function of shaft span length/shaft diameter (L/d).

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1992년도 춘계공동학술대회 발표논문 및 초록집; 울산대학교, 울산; 01월 02일 May 1992
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• pp.436-443
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• 1992

Presented in the paper is a systematic approach to constructing a Petri net model of FAS (flexible assembly system). Petri net is widely used in modeling automated manufacturing systems. But, it found to be very difficult for an FA engineer to build a correct model of an FAS with Petri net symbols (ie, place, transition, and token) from the beginning. An automated manufacturing system in general is built from a set of "standard" hardware components. An FAS in particular is usually composed of assembly robots, work tables, conveyor lines, buffer storages, part feeders, etc. In the proposed modeling scheme, each type of standard resources is represented as a standard "module" which is a sub Petri net. Then, the model of a FAS can be conveniently constructed using the predefined modules the same way the FAS itself is built from the standard components. The network representation of a FAS is termed a JR-net (job resource relation net) which is easy to construct. This JR net is then mechanically converted to a formal Petri net (to simulate the behavior of the FAS). The proposed modeling scheme may easily be extended to the modeling of other types of automated manufacturing systems such as FMS and AS/RS.ch as FMS and AS/RS.

• 전력전자학회논문지
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• 제9권2호
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• pp.150-157
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• 2004

본 논문에서는 아날로그형 전력 계통 시뮬레이터에 적용하고자 개발 중인 TCSC(Thyristor Controlled Series Capacitor) 시뮬레이터 시스템 제어기의 하드웨어와 소프트웨어 구성에 대하여 제시하고자 한다. 본 연구에서 개발하고자하는 TCSC 시스템의 제어기는 기존의 전력 계통 시뮬레이터의 여러 제어기들과 통합되어 전력 시스템의 특성을 제어하는 장치이기 때문에 제어기는 전력 시스템의 각종 주요 파라메터를 실시간으로 통신할 수 있어야 하며 주어진 시간 내에 제어 기능을 수행할 수 있어야 한다. 따라서, 이러한 요구 조건을 만족시키기 위해서는 제어기 하드웨어의 설계와 구성이 매우 중요하다 본 논문에서는 TCSC 시스템의 복합적인 기능 수행을 위한 제어기 하드웨어와 소프트웨어 구조에 대하여 제시하고자 한다. TSCS 제어기는 고속 부동 소수 연산이 가능한 DSP(Digital Signal Processor) 플랫폼과 실시간 RTOS(Real Time Operating System)로 구성되어 있다.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.79-84
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• 1999

This paper focus on investigating the influence of the amount of water ingestion and the engine speed on the joint reaction force of the connecting rod in engine. The connecting rod was modelled by MSC/PATRAN, the modal informations of it were obtained by the DMAP module in the MSC/NASTRAN, and the dynamic force history was computed through the flexible multibody dynamic simulation in DADS. To analyze the joint reaction force acting on the connecting rod, the 48 cases were investigated. The engine speed varies with 200, 700, 1600, 2400rpm and the volumetric ratio of water to the combustion chamber varies with 0, 10, 20, ..., 90, 95 and 97.5% . As the engine speed decreases and the amount of water ingestion increases, the joint reaction force increase. Especially when the amount of water ingestion exceeds the 70% of the volume of the combution chamber, the joint reaction force acting on the connecting rod is over the design strength.