• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2003년도 추계학술대회 논문집(III)
• /
• pp.287-294
• /
• 2003

본 논문은 철도차량의 출입문과 역사의 플랫홈 사이에서 승객의 승하차시에 발생할 수 있는 안전사고를 방지하기 위한 안전발판장치에 관한 것으로서, 특히 출입문의 개폐작동에 따라 연동하여 작동되는 안전발판을 구비하는 것에 의해 별도의 동력과 제어장치를 필요로 하지 않음은 물론, 오작동 없이 정확하게 동작되도록 한 철도차량의 안전발판장치에 관한 것이다. 일반적으로, 지하철 역사의 플랫홈과 철도차량 간에는 열차의 원활한 안전주행을 위해 일정한 간격(이하 "연단간격"이라 함)이 유지된다. 이러한 연단간격은 가능한 한 좁게 형성되도록 구축되는 것이 바람직하나 그러기 위해서는 역사를 직선으로 건설해야 하지만, 통상 지하철은 도심의 인구집중지역의 기존 대로를 따라 노선이 결정되어 공사가 이루어지므로 도시가스배관, 도로주변의 고층대형건물, 기존도로의 형상 및 지하수와 같은 여러 가지 조건에 의해 많은 역사들이 곡선부분을 포함하여 건설될 수밖에 없다. 이 때문에, 철도차량과 플랫홈 간의 연단간격이 크게 벌어지는 구간이 형성되어 짧은 정차시간에 많은 사람들이 승하차하면서 연단간격으로 승객의 발이 빠지는 등의 안전사고가 빈번히 발생하고 있다. 이와 같이, 연단간격이 커짐에 따른 사고발생을 줄이기 위하여 연단간격이 큰 부분에 경고등을 설치하거나 경보음을 발생시키는 방법을 사용하였다. 이러한 경보장치는 차량이 지정된 궤도로 진입하면, 경고등에서 빛을 발산하여 차량과 플랫홈 사이의 공간에 대한 위험성을 승객에게 주의시키면서 경보나 안내방송이 나오게 하고, 차량이 역사를 출발하여 궤도를 지나면 그 작동이 멈추는 장치이다. 그러나, 이러한 경보장치는 위험성을 승객에게 알려 승객 스스로가 위험에 대처하도록 하는 주의정보제공의 기능만을 가지는 장치로서, 바쁜 출퇴근 시간이나 혼잡한 상황에서는 만족할 만한 효과를 기대하기 어려웠고, 특히 위험 대처능력이 떨어지는 어린아이나 노약자에게는 위험성이 그대로 상존하는 문제점이 있었다. 이와 같은 문제점으로 인하여 경전철이 있는 나라에서는 경전철용 차량에 승객이 안전하게 승하차할 수 있도록 계단식 발판을 설치하는 차량용 발판이 제공되어 있으나, 국내 지하철에 적용하기에는 차체 및 역사의 구조상 불가능하였다. 차량의 바닥이 플랫홈과 거의 동일 레벨상에 위치하므로 안전발판이 차량의 바닥과 수평이 되도록 작동되어야 하고, 차량에 있어서도 스테인레스 차량인 경우 사이드 빔(Side beam), 알루미늄 차량인 경우 솔바(Sole bar)에 구멍을 뚫으면 전체적인 차체의 강도 및 구조상의 문제가 발생되기 때문이다. 본 논문에서 이전에 개발된 국내외 안전발판장치를 소개하고 연단간격과, 차량 플랫홈의 높이의 차이에서 발생하는 문제를 함께 해결하는 안전발판장치를 해결책으로 제시하고자 한다.

• 한국전자통신학회논문지
• /
• 제10권1호
• /
• pp.27-32
• /
• 2015

본 논문에서는 GNSS(Global-Navigation Satellite Service)에서 사용되는 단말기의 PCB(Printed Circuit Board) 전원안정화를 위해서 PCB 내층에 삽입될 EBG(Electromagnetic Band Gap) 구조체를 제안한다. 버섯모양의 제안된 EBG 구조체를 통한 PCB에서의 관심 금지대역폭/저지대역폭 주파수는 GNSS와 이동통신 관련 주파수를 포함하는 1.55GHz에서 1.81GHz이었으며, 시뮬레이션 결과, 이 구간에서 삽입손실(S21)이 약 -40dB 이하로 형성됨을 볼 수 있었다. 본 연구결과는 향후, PCB 회로 설계의 PDN(Power Delivery Network)구조의 안정화 향상 및 EMI(Electro Magnetic Interference) 대책에 효과적 대응이 유용할 것으로 기대된다.

• Journal of Welding and Joining
• /
• 제16권5호
• /
• pp.119-133
• /
• 1998

To implement full automation in pipe welding, it si most important to develop special sensors and their related systems which act like human operator when detecting irregular groove conditions. In this study, an automatic pipe Gas Metal Arc Welding (GMAW) system was proposed to full control pipe welding procedure with intelligent sensor systems. A five-axes manipulator was proposed for welding torch to automatically access to exact welding position when pipe size and welding angle were given. Pool status and torch position were measured by using a weld-pool image monitoring and processing technique in root-pass welding for weld seam tracking and weld pool control. To overcome the intensive arc light, pool image was captured at the instance of short circuit of welding power loop. Captured image was processed to determine weld pool shape. For weld seam tracking, the relative distance of a torch position from the pool center was calculated in the extracted pool shape to move torch just onto the groove center. To control penetration of root pas, gap was calculated in the extracted pool image, and then weld conditions were controlled for obtaining appropriate penetration. welding speed was determined with a fuzzy logic, and welding current and voltage were determined from a data base to correspond to the gap. For automatic fill-pass welding, the function of human operator of real time weld seam control can be substituted by a sensor system. In this study, an arc sensor system was proposed based on a fuzzy control logic. Using the proposed automatic system, root-pass welding of pipe which had gap variation was assured to be appropriately controlled in welding conditions and in torch position by showing sound welding result and good seam tracking capability. Fill-pass welding by the proposed system also showed very successful result by tracking along the offset welding line without any control of human operator.

• Journal of Welding and Joining
• /
• 제20권3호
• /
• pp.122-128
• /
• 2002

The laser welding in the automotive industries has been used widely for the butt joint of blank sheets rather than the lap joint of automotive body panels. But as a substitute far the spot welding of automotive body panels, the so called three dimensional laser welding will be important far the body panel engineers. Specially the laser welding of body panels with a smooth weld line is applied increasingly, for example, to the side panels. So far, some criteria of the laser weld quality was suggested by in-house regulations or national standards from experiences and/or rule of thumbs. In the manufacturing places, a go or no-go criterion is adopted because of the simplicity or a lack of rational criteria. It is true specially for the selection of the process parameters, which gives the basic causes for the good quality of laser welds. In this study, the effects of joint combination, gap and welding speed on the lap joint $CO_2$ laser welding of two mild steel sheets with different thicknesses are obtained through a $2{\times}3{\times}7$ factorial experiment. The results of the weld quality are statistically analysed using analysis of variance (ANOVA) and compared between two characteristic zones, which are separated by the type of sectional shapes and the level of input energy per volume. The thickness combinations are 0.8mm/1.2mm, 1.2mm/0.8mm of mild steel sheets. The welding speed covers from the deep penetration to the partial penetration. The gap size has three levels of no-gap, 0.16m, and 0.26mm. The bead width, penetration depth and input energy per volume are measured and used as the weld quality criteria.

• Agribusiness and Information Management
• /
• 제10권1호
• /
• pp.1-15
• /
• 2018

Many paddy cultivating farmers in the country are forced to use their limited resources to produce adequate food for their family, leading to the degradation and reduction in potential of these resources. The yield levels of paddy at the farmers' level and in the Front Line Demonstrations (FLDs) conducted in the farmers' fields is not at par with potential yield of the paddy variety. The gap between potential yield of crop variety and yield realized in FLDs refers to Research gap and the yield gap between FLDs and due to farmers' practice refers to Extension gap. The earlier studies conducted in India in general and in Andhra Pradesh in particular highlighted the existence of both research and extension gaps with reference to paddy. It is essential that, the narrowing of both research and extension gaps is not static, but dynamic considering the influence of technological interventions in boosting paddy yields at FLDs level and at farmers' level and also with the improvement of the yield potential of paddy varieties. This calls for integrated and holistic approaches to address these two gaps and with this background, the researcher aimed at this in depth study. The findings revealed that, research gaps are high with reference to weed management and pest management and extension gaps are high with reference to farm mechanization followed by fertilizer management. Reliable source of seed, capital use and frequency of meetings with Scientists or Agricultural Officers significantly influence the extension gaps in paddy. Farmers also prioritized socio-economic and technical constraints and the analysis infers that, it is high time now for the farmers to adopt the planned technological interventions on scientific scale to minimize the extension gaps to the extent possible. As the enabling environment in the State of Andhra Pradesh is highly encouraging for the farmers with relevant policy instruments in the form of subsidized inputs, free power, credit at concessional rates of interest, constructing irrigation projects etc., the adoption of the proposed technological interventions significantly contribute to minimizing both research and extension gaps in paddy cultivation in Kurnool district of Andhra Pradesh.

• 한국컴퓨터정보학회논문지
• /
• 제23권11호
• /
• pp.111-122
• /
• 2018

The purpose of this study was to investigate the bodice prototype method suitable for the upper body shape of old-old aged women using the 3D anthropometric data. And it was to provide the basic data for the upper body garments of old-old aged women. In the overall appearance evaluation, the B pattern was rated as 4.00, and it was evaluated as the most suitable for the bodice prototype of the old-old aged woman. The E pattern was rated lower than normal, and the L pattern and the S pattern were found to be inadequate for older female bodice prototypes. As a result of the measurement of the waist and bust air gap of bodice prototype, the air gap of the bust was not significantly different between the patterns. But the waist air gap showed the largest difference between the L pattern and the S pattern. As a result of evaluating the appearance, the amount of space in the state of 3D simulation, and the air gap, the pattern B appeared to be the most appropriate prototype for the old-old aged women's body shape. However, there is a tendency that the shoulder end point is biased toward the back, so it is necessary to set the inclination of the back shoulder line to be more gentle. Conversely, the front shoulder should be more inclined. In the case of the 3D simulation, the B pattern showed that the other parts generally fit well. In the case of the 3D simulation program used in this study, it was evaluated that it is suitable only for the normal body shape because it is impossible to set the isometric angle which is one of the characteristics of the older female body shape. A study on the bodice prototype suitable for the bent body shape should be carried out through experiments on the actual body shape of various elderly women. In order to cope with the increase of elderly people who are familiar with digital, I think it is necessary to develop an avatar that reflects the old female body shape.

• Journal of electromagnetic engineering and science
• /
• 제5권4호
• /
• pp.204-207
• /
• 2005

In this paper, PBG structure and feedforward circuit has been used to suppress the phase noise of the oscillator. Microstrip line resonator have low Q, but we can obtain high LO power by feedforward circuit and improve the resonator Q by the PBG, simultaneously. The proposed oscillator which uses PBG and feedforward circuit shows 0${\~}$20 dB phase noise reduction compared to the conventional oscillator. We have obtained -115.8 dBc of phase noise at 100 kHz offset from 2.4 GHz center.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
• /
• pp.7-10
• /
• 2002

This paper presents a design of 24㎓ GaAs MESFET voltage controlled oscillator using a dielectric resonator(DR) and a frequency doubler. DR modeling has been done to get the effects of resonator size and the gap from transmission line by HFSS at 12㎓, and frequency doubler is used to get 24㎓ Output.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 하계종합학술대회 논문집
• /
• pp.966-969
• /
• 1999

Using modal transmission-line theory (MTLT), we evaluate the power coupling of optical directional coupler composed by two parallel guiding slabs. The numerical results reveal that maximum power transfer occurs at a novel wavelength λ$_{opt}$, in which the excitation ratio of supermodes at input boundary is equal to each other, and it is generally different from minimum gap λ$_{min}$.in/.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2015년도 제46회 하계학술대회
• /
• pp.802-803
• /
• 2015

본 논문에서는 영구자석 동기전동기의 극수와 Slot수 조합에 따른 특성을 분석하고 비교해 보았다. 동기전동기의 극수를 8극으로 고정하고 Slot의 수를 9,12,30,42 Slot으로 설정하고, 이에 따라 Flux Line, Air Gap Flux, 토크특성, 역기전력을 각각 분석하였다. 또 사용용도에 따라 적합한 극수 Slot수 조합을 제시하였다.