• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.1
• /
• pp.172-182
• /
• 2000

A hybrid type automotive drivers seat was invented with new concepts for the reduction of weight and manufacturing costs. Fundamental studies were performed to determine the basic geometry of reinforcing support. A prototypical design was provided by the manufacturer considering compatibility with other parts. Several structural analyses simulating various crash situations were performed and modifications were continued until a final design was reached. A sample product was manufactured and sled crash tests were performed to verify the safety of the seat. Comparisons of test results with the previous model and a seat from another company proved safety performances to be superior.

• Computational Structural Engineering
• /
• v.11 no.4
• /
• pp.383-390
• /
• 1998

0.93m/sec의 평균속도는 변위제어 삼점휨 실험된 콘크리트 보의 하중-변위 측정결과를 선형탄성파괴역학모델과 가상균열모델에 기초한 유한요소법으로 분석하였다. 두 모델 모두 실험결과와 잘 일치하며, 균열성장길이가 약 60∼70㎜가 될 때까지 안전된 균열성장을 보이다 불안정한 균열성장에 의해 파손되었다. 선형탄성파괴역학모델에 의한 수치해석 결과 에너지해방률은 균열성장길이에 비례해서 증가하였으며, 최대값(202N/m)에 이르게 되면 일정한 값을 유지하였다. 가상균열모델에 기초한 수치해석결과 이 연구에 사용된 하중속도와 시험편의 크기에 대해 70㎜의 완전한 파괴진행대가 평성되었으며, 이는 기존의 정적 실험결과에 대한 수치해석 결과보다 상당히 작은 값이었다.

• Journal of Applied Reliability
• /
• v.2 no.1
• /
• pp.1-14
• /
• 2002

High temperature operating test, temperature humidity test and temperature cycling were performed at various test levels for solid aluminum electrolyte capacitors made by domestic manufacturing company and foreign advanced manufacturing company. It was found that main failure mode of solid aluminum electrolyte capacitors was the decrease of their capacitances. The decrease of their capacitances has the same pattern in these tests. Test result for comparison of characteristics between domestic products and foreign advanced products shows that domestic products have the shorter lifetime and their capacitances decrease more rapidly in high temperature operating test and temperature humidity test. Also in these tests, accelerated tests for high temperature operating test and temperature humidity test were developed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.727-730
• /
• 2004

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MD-ARS) might be one candidate of several systems against the ship's rolling. In this paper, three types of MD-ARS, two passive and one active devices, are developed for small ships. After they are installed on the cabin of the small leisure boat, respectively, a series of test is conducted before and after operating them. Through the test, it is confirmed that the roll responses of the ship are pretty well reduced by the system.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.9
• /
• pp.2221-2226
• /
• 2009

This paper presents the design of the LED sign board system installed on the exterior of a building and powered by a photovoltaic system. A grid connected photovoltaic system has been designed with the capacity estimate of the load, battery and power. After the luminance and uniformity of LED load has been checked, the sign board and the solar cell modules have been installed. The performance and problems occurred during the field test for the photovoltaic LED sign board system have been analyzed.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2021.05a
• /
• pp.55-58
• /
• 2021

우주 네트워크는 고지연성, 저신뢰성 등 기존의 지상 네트워크와는 차별화된 특성을 가진다. 또한 높은 예산이 투입되는 우주 임무 특성상 지상 시험 시 발견되지 않은 소프트웨어 버그가 막대한 비용을 초래할 수 있다. 그러나 현재까지 우주 네트워크 환경에 특화된 소프트웨어 업데이트 관련 연구는 부족한 실정이다. 따라서 본 연구에서는 Asynchronous Management Protocol(AMP)을 기반으로 원격 소프트웨어 업데이트 프레임워크를 새롭게 제안한다. 해당 프레임워크는 Interplanetary Overlay Network(ION) 소프트웨어를 사용하여 프로토타입을 구현하였으며, 실제 업데이트 케이스를 적용하여 기능 및 실사용성을 검증하였다.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.7
• /
• pp.49-56
• /
• 2011

Recently, the ground injection method using water glass as one of the components of the main resources and the products of the construction has some basic problems for permanent reinforcement of foundation and stopping leakage of water because it has some serious problems such as durability reduction, compression strength reduction and eluviation. This study was to evaluate the environmental impact and durability of the developed friendliness of Natural and Durable Stabilizer(NDS) of inorganic injection and Space Grouting Roket(SGR) with typical water glass type material. Two materials, NDS and SGR, were compared with each other by unconfined compressive strength test, fish poison test, durability test and triaxial permeability test. The results of the durability test indicated that the 28-day strength of the NDS was 1.5 times higher than that of the SGR. The fish poison test proved that the survival rate in the SGR and NDS is 50~70%, and 100%, respectively. Therefore, the NDS has higher survival rate than that of the existing SGR. The NDS will be considered by an environmentally friendly product and moreover it has a few problems for soil and groundwater pollution.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.12
• /
• pp.1045-1059
• /
• 2011

A 3-D multi-function radar(MFR) is a modern radar to provide various target information, such as range, doppler, and angle by performing surveillance, multiple target tracking, and missile guidance. In this paper, we introduced a real-time radar signal processor(RSP), which is a crucial component of MFR with its design, implementation using high-speed multiple DSP, and performance. Additionally, we verified that several advanced signal processing algorithms were well-performed in our RSP, such as MCA-CFAR algorithm for target detection in clutter environment, range and velocity measurement algorithm using discriminator estimation, and noise jammer detection algorithm using local minimum selection.

• Journal of Aerospace System Engineering
• /
• v.12 no.4
• /
• pp.106-111
• /
• 2018

Hydrodynamic ram phenomenon could be generated by external threats such as impact and blast in the aircraft. High strain rate deformation caused by the hydrodynamic ram phenomenon is one of the main factors to influence structural survivability. Mechanical properties of composite structure change rapidly under conditions of high strain rate. Therefore, it is necessary to experimentally investigate the influence of strain rates for aircraft structural survivability. In this paper, tensile tests of composite material were conducted for low and high strain rates to investigate the influence of the various strain rates. Tensile modulus increases more compared to tensile strength at high strain rate under hydrodynamic ram condition. Regression analysis was conducted to predict tensile modulus at various strain rates because it is one of the main damaging factors for composite structures under high strain rate conditions. Also, the mechanical properties of composite materials were acquired and analyzed under high strain rate conditions. It is hypothesized that the results from this study would be used for designing aircraft composite structures and evaluation considering structural survivability.

• Journal of the Society of Naval Architects of Korea
• /
• v.34 no.2
• /
• pp.27-38
• /
• 1997

This paper is concerned with the calculation of the wave resistance for SWATH ships based on a low order Rankine source panel method. Two types of free surface boundary conditions, Dawson type (double model approximation) and Kelvin type (free stream approximation) are used. For the free surface boundary calculation, an analytic differentiation is employed instead of implementing a finite difference scheme. Then, the radiation condition is satisfied by, so called, the panel shift method. The numerical results using the above two methods are compared with those using the thin ship/modified slender body approximation and also with the experimental results. The SWATH models considered are a single strut SWATH and a twin strut SWATH together with the variations of two demihull separation distance. In order to prove the validity of the program developed, the numerical calculations for a Wigley mono hull and Wigley twin hulls are compared with the available experimental results.