• Journal of Advanced Navigation Technology
• /
• v.21 no.5
• /
• pp.491-500
• /
• 2017

This paper investigates a low cost dual modular redundancy system based on heartbeat which can be applied to traffic control signal system. Failure of the traffic control signal system can cause traffic confusion and traffic accidents. Therefore safety and reliability of traffic control should be secured using fault tolerance technology. To do this, we configured a redundant board using the open source hardware and the heartbeat technique of Linux HA. The function of the traffic signal control system was verified and the fault recovery time was measured using fault injection test. As a result of the test, the fault recovery time was confirmed to be less than 9 seconds on average, confirming that the reliability target time is satisfied. Based on the results of this study, it is expected that it can be applied to fields requiring high reliability systems such as aviation, space, and nuclear power embedded systems.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.210-210
• /
• 2011

하도에서의 하천정비 및 안전하도 유지를 위해서는 하상변동 특성을 면밀히 파악하는 것이 중요하다. 상류유역에서 하천으로 내려온 유사(流砂)는 하천의 흐름과 생태환경에 영향을 미친다. 이중 하천흐름은 사련(ripple)이나 사구(dune)의 형성에 영향을 미쳐, 하천의 지형변동인 사주에 영향을 주고 하천 식생의 성장과 발달에 직 간접적으로 간섭하게 된다. 또한, 교량, 취수장의 취수장애, 호안블럭의 침식 등과 같이 수리구조물의 안정에 영향을 주게 된다. 하천의 유사량 변화에 따라 생태계의 서식환경이 변하게 된다. 또한, 저수지에서 유입 유사량의 변화에 따라 저수지의 용적이 변하게 되어 댐의 설계 및 운영에 많은 영향을 끼치게 되며 특히 저수지 탁수관리에 매우 중요하다. 본 연구에는 4개 대권역의 주요지천 및 댐 직 하류하천 지점 중 적정구간을 선택하여 하상재료조사를 실시하였다. 하상재료 조사는 하도를 구성하는 모래와 자갈의 물리적 성질 중 유사의 이동량 및 하상의 변동, 하도설계 등에 관련 있는 입도분포, 비중 등을 측정하며 자갈하천은 표층 하상재료를 조사하고, 모래 재료는 체분석, 실트이하 재료는 BW관 등을 이용한 침강속도 분석을 실시한다. 주요지점의 중 남강의 안의 수위 우량관측소 지점의 상 하류 2km 구간을 200m마다 21개 지점의 하상재료를 채취하여 입도분석을 실시하였다. 분석결과 남강 안의지점의 표층은 여느 하천과 마찬가지로 상 하류 굵은 자갈로 구성되어 있으며 전형적인 자갈하천의 특성을 보었다. 상류200m(2000m)에서는 최소 50mm(10mm), 최대 440mm(75mm), 평균입경은 174mm(34.7mm) 이었고, 하류200m(2000m)에서의 표층입경은 최소 8mm(25mm), 최대 50mm(110mm)이며 평균입경은 27.3mm(62.5mm)로 구성되어 있었다. 전체적으로 상류지역의 입경이 하류지역보다 큰 것을 관찰할 수 있었으며 유수 흐름의 일시적인 저항이 발생하는 안의교 지점의 자갈 입경이 인근 부근보다 큰 것을 확인할 수 있었다.

• KIISE Transactions on Computing Practices
• /
• v.22 no.2
• /
• pp.113-118
• /
• 2016

The walking speed of handicapped people generally is slower than that of normal people. So it is difficult for them to cross at crosswalks within the allotted time provided by the traffic light. This problem can be solved by expanding the time of the traffic light. However, if the latency of the traffic light is increased without distinguishing the handicapped among all other pedestrians, the efficiency of traffic signal lights will decrease. In this paper, we propose a smart traffic signal connecting mechanism between the previous pedestrian traffic signal and a pedestrian's device (smartphone). This Smart pedestrian traffic light, through this mechanism, minimizes traffic congestion by providing additional walking time only to the handicapped among pedestrians. This crosswalk traffic light recognizes the handicapped using a technique called Internet of things (IOT). In this paper, we extract the data necessary to build an effective smart crosswalk traffic light mechanism through simulation techniques. We have extracted different kinds of traffic signal times with our virtual simulation environment to verify the efficiency of the smart crosswalk pedestrian traffic light system. This approach can validate the effective delay time of the traffic signal time through a comparison based on number of pedestrians.

• Tunnel and Underground Space
• /
• v.27 no.6
• /
• pp.387-392
• /
• 2017

Recently, road cave-ins, also referred to as ground sinking, have become a problem in urban environments. Public utility facilities such as sewage pipelines, communications pipes, gas pipes, power cables, and other types of underground structures are installed below the roads. It was reported that cave-ins are caused by the aging and lack of proper maintenance of underground facilities, as well as by construction problems. A road cave-in is first initiated by the formation of cavities typically induced by the breakage of underground pipelines. The cavities then grow and reach the base of the pavement. The traffic load applied at the surface of the roads causes an abrupt plastic deformation. This type of accident can be considered as a type of disaster. A road cave-in can threaten both human safety and the economy. It may even result in the loss of human life. In the city of Seoul, efforts to prevent damage before cave-ins occur have been prioritized, through a method of discovering and repairing joints through the 3D GPR survey.

• Journal of Chest Surgery
• /
• v.32 no.1
• /
• pp.10-15
• /
• 1999

Background: Mitral valve replacement with chordal preservation in patients with mitral regurgitation has been proved to be beneficial for left ventricular function and for reduction of postoperative complication. However, in patients with mitral stenosis, the effectiveness of the technique is controversial. It is not easy to insert prosthetic valve without left ventricular outflow tract obstruction and prosthetic valve leaflet motion hinderance. Material and Method : Five patients with mitral stenosis and seven patients with mitral stenoinsufficiency underwent mitral valve replacement with preservation of mitral subvalvular apparatus. Thickened and calcified leaflets are made thin by peeling off the thickened and calcified part. Commissurotomy was done and anterior leaflet was incised 2 mm apart from the annulus and then divided into two segments. Anterolateral and posteromedial segments including strut chordae, were reattached to mitral commissural area, respectively. Result: There was no evidence of prosthetic valve dysfunction, paravalvular leakage, left ventricular outflow tract obstruction, complications and operative or late deaths. Conclusion: We conclude that mitral vlave replacement with chordal preservation was safe and effective technique for the patients with mitral stenotic disease.

• Journal of Information Technology Services
• /
• v.16 no.4
• /
• pp.223-234
• /
• 2017

The audible pedestrian signal (APS) is an add-on device which connects to the pedestrian signaling device and informs the contents and changes of the signaling by sound. It provides walking direction information of the pedestrian crossing so that the blind people can safely cross the pedestrian crossing. In an intersection where a plurality of audible pedestrian signal (APS) are installed at an intersection crosswalk, existing audible pedestrian signal (APS) operate simultaneously in the communication radius of a wireless remote controller, which may cause confusion for the blind people and the public may complain about the noise. In this paper, we developed a BLE (Bluetooth Low Energy)-based audible pedestrian signal (APS) system capable of supporting two-way communications with a smart-phone that can cross the intersection safely and improve the walking comfort and traffic safety for the blind people. The proposed method is a method in which the BLE beacon communication based audible pedestrian signal (APS) presents active service to the blind people, and the existing audible pedestrian signal (APS) is a way of requesting the passive service by the blind people with the wireless remote control by the unidirectional communication based on 358Mhz. The developed system is installed in the crossroad of Doma-dong, Seo-gu, Daejeon, and it is tested and operated by the blind people. The satisfaction evaluation and analysis of the audible pedestrian signal (APS) for the blind people have good results and are planned to be expanded in the future.

• Aerospace Engineering and Technology
• /
• v.3 no.1
• /
• pp.242-250
• /
• 2004

This paper describes the detection method of wire-like obstacles using millimeter-wave radar system. Passive sensor like CCD camera can be used for the detection of high power electric cables on the hills or mountains and it can give very good quality of obstacle target information. But this system is very limited to use by bad weather condition. The detection capability for different diameters of wire targets using millimeter radar system have been accomplished. To simulate the target on the moving helicopter, rotating targets are used with fixed radar system. In the experiment 11mm, 16mm and 22mm diameter of wires have been detected in single, two and three wires in one position. The detected signal from single wire was very clear on gray level image. Three wires placed very closely together could be recognized in range, cross range image plane. For two and three wires, blur effect due to mutual scattering effect is observed.

• The Journal of the Korea Contents Association
• /
• v.20 no.1
• /
• pp.448-459
• /
• 2020

Recently, the necessities of gathering, producing, and sharing criminal information are critically important as intelligence functions of police agencies to improving public safety and national security. However, the inadequacies and barriers within which police agencies have in regard to intelligence functions impede criminal information gathering, intelligence producing within their agency, and intelligence sharing with other agencies. In this study, we analyzed informal networks constructed from a survey dataset of information and intelligence sharing among officers in police agencies. The results revealed the different structural properties of intelligence networks between police agencies. We did find that officers with high indegree and outdegree in a network played critical role on the dynamics and degree of intelligence gathering and assessment responsibilities. Finally, we could find evidence that the potential role of intermediary triggered relational dynamics for developing and sharing critical information among all police agencies.

• Clinical and Experimental Pediatrics
• /
• v.50 no.8
• /
• pp.752-756
• /
• 2007

Purpose : The aim of this study was to compare 2 laxatives, namely, polyethylene glycol 4000 without electrolytes and lactulose, evaluating the efficacy and safety for the treatment of constipation in children. Methods : Fifty-six children with chronic functional constipation were randomly assigned to receive polyethylene glycol 4000 (24 patients) or lactulose (32 patients). Patients or their parents reported defecation frequency, stool consistency, abdominal pain, stool incontinence and side effects after 1, 3, 6 and 12 months of treatment. Percentage of recovered patients were compared with each group. Results : Defecation frequency, abdominal pain and stool incontinence were improved in each group. At 12 months of follow up, 60% of patients treated with polyethylene glycol and 57.7% of patients treated with lactulose were considered as recovered. Conclusion : In this study, both polyethylene glycol and lactulose were equally effective and safe in the long-term treatment of constipation in children. There were no significant differences in recovery rates between 2 groups.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.717-719
• /
• 2015

The research and development of the unmanned vehicle is being carried out actively in domestic and foreign countries. The research is being carried out to provide various services so that the weakness of system such as conventional 2D-based navigation systems can be supplemented and the driving can be safer. This paper suggests the method that enables real-time video processing in more efficient way by realizing the location detection and signal recognition technique of traffic signals in video. In order to overcome the limit of conventional methods that have a difficulty in analyzing the signal as it is sensitive to brightness change, the proposed method realizes the program that grasps the depth data in front of the vehicle using video processing, analyzes the signal by detecting traffic signal and estimates color components of traffic signal in front and the distance between traffic signal and the vehicle.