• Title/Summary/Keyword: safety verification

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3-D Numerical Analysis for the Verification of Bearing Mechanism and Bearing Capacity Enhancement Effect on the Base Expansion Micropile (선단 확장형 마이크로파일의 3차원 수치해석을 통한 지지 메커니즘 및 지지력 증대효과 검증)

  • Lee, Seokhyung;Han, Jin-Tae;Jin, Hyun-Sik;Kim, Seok-Jung
    • Journal of the Korean Geotechnical Society
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    • v.37 no.2
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    • pp.19-31
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    • 2021
  • Micropiles are cast-in-place piles with small diameters. The advantage of micropile is low construction expense and simple procedures, so it is widely applied to existing buildings and structures for the reinforcement of foundation and seismic performances. The base expansion structure has been developed following the original mechanism of horizontal expansion steps under compressive loading. This kind of structure can be installed at the pile end to improve the bearing capacity by tip area enlargement and horizontal force increment to the pile surface area. However, 'Micropile with base expansion structure' cannot be put into practical use, because detailed verification for the developed technique has not been conducted so far. In this research, 3-D numerical analysis was conducted to figure out the bearing mechanism of base expansion micropile and to verify the bearing capacity improvement compared to the general micropiles. 3-D modelling of micropile with base expansion structure was carried out and input parameter was determined. Bearing mechanism induced by base expansion structure was analyzed by lab-scale modelling, and bearing capacity improvement was verified by field-scale analysis.

A Study on the Risk Analysis and Fail-safe Verification of Autonomous Vehicles Using V2X Based on Intersection Scenarios (교차로 시나리오 기반 V2X를 활용한 자율주행차량의 위험성 분석 및 고장안전성 검증 연구)

  • Baek, Yunseok;Shin, Seong-Geun;Park, Jong-ki;Lee, Hyuck-Kee;Eom, Sung-wook;Cho, Seong-woo;Shin, Jae-kon
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.20 no.6
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    • pp.299-312
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    • 2021
  • Autonomous vehicles using V2X can drive safely information on areas outside the sensor coverage of autonomous vehicles conventional autonomous vehicles. As V2X technology has emerged as a key component of autonomous vehicles, research on V2X security is actively underway research on risk analysis due to failure of V2X communication is insufficient. In this paper, the service scenario and function of autonomous driving system V2X were derived by presenting the intersection scenario of the autonomous vehicle, the malfunction was defined by analyzing the hazard of V2X. he ISO26262 Part3 process was used to analyze the risk of malfunction of autonomous vehicle V2X. In addition, a fault injection scenario was presented to verify the fail-safe of the simulation-based intersection scenario.

Verification of Reliability by the Induced Voltage of a Downscaled and Simulated 22.9kV-Y Distribution Line (축소 모의된 22.9 kV-Y 배전선로의 유도 전압에 대한 신뢰성 검증)

  • Kim, Jeom-Sik;Choi, Chung-Seog
    • Journal of the Korean Society of Safety
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    • v.30 no.4
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    • pp.26-31
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    • 2015
  • The purpose of this paper is to measure the induced voltage of the downscaled and simulated overhead ground wire of a 22.9kV-Y distribution line. This study performed a test of the downscaled and simulated distribution line according to whether it is grounded or not and the value of the ground resistance. In order to verify the reliability of the data measured by the test, the data was analyzed using the Minitab 17 program. It was found that the induced voltage of the downscaled and simulated distribution line is influenced by the value of the ground resistance. It was also found that the ground resistance obtained at a certain point is closely related to whether electric poles are grounded or not. The analysis results of the measured test data with a statistical method showed that the Anderson Darling (AD) was analyzed to be the smallest as 0.188 when the ground resistance of the electric poles had been maintained at $10{\Omega}$. In addition, the P value analyzed to be 0.894 which is in the proximity of the theoretical value of 1 and verified the reliability of the test data. It could be seen that the data measured by the downscaled simulation test forms a linear graph. It is thought that if a distribution line is installed in the same manner as the downscaled, simulated distribution line, the mean induced voltage will be reduced and reliability will be increased.

A Proof of Safety and Liveness Property in Modal mu-Calculus and CTL for Model Checking (모형검사를 위한 Modal mu-Calculus 와 CTL의 안전성 및 필연성 및 논리식 증명)

  • Lee, Bu-Ho;Kim, Tae-Gyun;Lee, Jun-Won;Kim, Seong-Un
    • Journal of KIISE:Computer Systems and Theory
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    • v.26 no.12
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    • pp.1485-1492
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    • 1999
  • 대규모 시스템 명세의 올바름을 검증하기 위한 유한 상태 LTS에 기반을 둔 CTL논리 적용에 있어 가장 큰 문제점은, 시스템 내부의 병렬 프로세스간의 상호작용으로 인한 상태폭발이다. 그러나 Modal mu-calculus 논리를 시스템 안전성 및 필연성 특성 명세에 사용하면, 행위에 의한 순환적 정의가 가능하므로 상태폭발 문제가 해결 가능하다. 본 논문에서는 LTS로 명세화된 통신 프로토콜 시스템 모델의 안전성 및 필연성 특성을 모형 검사 기법에 의해 검증함에 있어, 시제 논리로 사용된 Modal mu-calculus 안전성 및 필연성 논리식과 CTL 의 안전성 및 필연성 논리식의 극한값이 동일함을 두 논리식을 만족하는 상태 집합이 같다는 것을 보임으로써 증명한다. 증명된 결과는 I/O FSM 모델로 표현된 통신 프로토콜의 안전성 및 필연성 검사를 위해 이론적인 기반으로서, 컴퓨터를 이용한 모형검사 기법에 효과적인 방법으로 응용이 가능하다.Abstract In applying CTL-based model checking approach to correctness verification of large state transition system specifications, the major obstacle is the combinational explosion of the state space arising due to interaction of many loosely coupled parallel processes. If, however, the modal mu-calculus viewed as a CTL-based logic with recursion, is used to specify the safety and liveness property of a given system, it is possible to resolve this problem. In this paper, we discuss the problem of verifying communication protocol system specified in LTS, and prove that a logic expression specifying safety and liveness in modal mu-calculus is semantically identical to the maximum value of the expression in CTL. This relation is verified by the proof that the sets of states satisfying the two logic expressions are equivalent. The proof can be used as a theoretical basis for verifying safety and liveness of communication protocols represented as I/O FSM model.

Relationship between Adaptation Luminance and Threshold Zone Luminance for Vehicular Traffic Tunnels (터널 순응휘도와 경계부 휘도의 관계 연구)

  • Cho, Won Bum;Jeong, Jun Hwa
    • International Journal of Highway Engineering
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    • v.16 no.3
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    • pp.85-99
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    • 2014
  • PURPOSES : This study has been performed with the objective to determine threshold zone luminance of adaptation luminance by target safety level in a vehicular traffic tunnel with design speed set at 100km/h. METHODS : The study made a miniature capable of portraying changes in luminance distribution within $2{\times}10^{\circ}$ conical field of view of the driver approaching to the tunnel for the test. Test conditions were set based on justifications for CIE 88-1990's threshold zone luminance used as a reference by domestic tunnel light standards (KS C 3703 : 2010). Luminance contrast of object background and object is 23%, object presentation duration is 0.5 seconds, and size of the object background is $7.3{\times}11.5m^2$ RESULTS : Threshold zone luminance was set within adaptation luminance of $100{\sim}3,000cd/m^2$. Adaptation luminance and threshold zone luminance based on 50%, 75% and 90% target safety level all showed a relatively high linear relationship. According to findings in the study, it is not appropriate to specify the relationship between adaptation luminance and threshold zone luminance as luminance ratio. Rather, direct utilization of the linear relationship gained from the study findings appears to be the better solution. CONCLUSIONS : Findings of this study may be used to determine operation of threshold zone luminance based on target safety level. However, a proper verification and validity of test results are required. Furthermore, a study to determine proper threshold zone luminance level considering target safety level reviewed in this study and various decision-making factors such as economic conditions in Korea and energy-related policies should be carried out in addition. Additional tests on adaptation luminance greater than $3,000cd/m^2$ will be performed, through which application scope of the test findings will be broadened.

A Study on the Development of Test Facility for Safety System Software V/V in Nuclear Power Plant (원자력발전소 안전계통 소프트웨어의 확인/검증을 위한 시험장치 개발에 관한 연구)

  • Lee, Sun-Sung;Suh, Young;Moon, Chae-Joo
    • Journal of Energy Engineering
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    • v.7 no.1
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    • pp.96-102
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    • 1998
  • The use of computers as part of nuclear safety systems elicits additional requirements-software verification and validation (v/v), hardware qualification-not specifically addressed in general industry fields. The computer used in nuclear power plants is a system that includes computer hardware, software, firmware, and interfaces. To develop the computer systems graded with nuclear safety class, the developing environments have to be required in advance and the developed software have to be verified and validated in accordance with nuclear code and standards. With this requirements, the test facility for Inadequate Core Cooling Monitoring System (ICCMS) as one of safety systems in the nuclear power plants was developed. The test facility consists of three(3) parts such as Input/Output (I/O) simulator, Plant Data Acqusition System (PDAS) cabinets and supervisory computer. The performance of the system was validated by manual test procedure.

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An Analysis of Effects of Travel Speed Using the Safety Facilities in the School Zones (어린이 보호구역내 교통안전시설이 구간통행속도에 미치는 효과 분석)

  • Lee, Ho-Won;Joo, Doo-Hwan;Hyun, Cheol-Seung;Kim, Dong-Hyo;Park, Boo-Hee;Lee, Choul-Ki
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.11 no.3
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    • pp.124-132
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    • 2012
  • There is high probability of children's traffic accidents. Because their physical, mental attribute are weak. Major part of the accidents happen during walking. Above all, jaywalking is the biggest traffic accident reason. Many traffic accidents take place on the road to school or near the home area. So Ministry of Public Administration and Security legislated children safeguard zone since 1995. But a study are inadequate the safety facilities on the effectiveness verification in the school zone. Therefore, this study aims to analyze the effectiveness of safety facilities. The vehicle speed is a direct correlation traffic accident. So in this study, the MOE(Measure of Effectiveness) is average travel speed in the school zone. The results shows that hump, rised pedestrian crossing has an effect.

Study on Obstacle Deflector of a Railway Vehicle Using Tension-type Energy Absorbers (인장형 에너지흡수부재를 이용한 철도차량용 장애물제거기 연구)

  • Kim, Hongeik;Kim, Jinsung;Kwon, Taesoo;Jung, Hyunseung
    • Journal of the Korean Society for Railway
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    • v.20 no.2
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    • pp.173-181
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    • 2017
  • The obstacle deflector sweeps obstacles off the track or absorbs crash energy with an energy absorber to prevent derailment of a train and to minimize damage and casualties after an accident. In this study, an obstacle deflector and its operational mechanism were designed with a tension-type energy absorber and a 4-bar linkage system. Also, a test method was suggested and verified with FEA (Finite Element Analysis) and UTM (Universal Test Machine) for testing of the static load and energy absorbing ability according to EN 15227 regulations. Through this study, an obstacle deflector that meets the EN 15227 standard was designed and a test method was suggested to adjust the collapse load easily and to verify it experimentally according to the design and verification procedure of the obstacle deflector.

Effects of Ground Faults on the Safety of Persons and Low-voltage Installations in 22.9 kV-Y Distribution Systems (22.9 kV-Y 계통에서 지락고장이 인체 및 저압설비의 안전에 미치는 영향)

  • Kim, Han-Soo;Chung, Jae-Hee;Kang, Kae-Myung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.1
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    • pp.141-148
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    • 2008
  • This paper presents experimental results on the safety of persons and protection of low-voltage equipments of the sub-station due to a single-phase ground fault in 22.9 kV-Y distribution system. In order to evaluate the hazard voltages and the stress voltage of the low-voltage(LV) equipment due to faults between high-voltage systems and earth based on the newly prescribed KS C IEC 60364 standard series, the verification tests in a 22.9[kV] neutral multiple grounding system were carried out. From the experimental results, we introduce serious problems causing some discomfort when applying KS C IEC 60364 standard series to the existing domestic distribution system and the effective protective measures against temporary overvoltages due to a ground fault in the common grounding which is combined the 22.9 kV-Y grounding and the customer's installation grounding are proposed. As a consequence, it was found that the equipotential bonding is an important prerequisite for the effectiveness of the protective measures for the safety of persons and LV equipment in the combined 22.9 kV-Y and low-voltage grounding system.

A Study on the Establishment of Concept and Selection criteria of Intelligent Security Technology Test-bed based on Spatial Information (공간정보 기반 지능형 방범 실증지구 개념 정립 및 선정기준에 관한 연구)

  • Shin, JuHo;Han, SunHee;Lee, JaeYong
    • Spatial Information Research
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    • v.22 no.6
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    • pp.45-54
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    • 2014
  • Establishment of safety net for the socially disadvantaged attracts large attention because of the recent crime increasing against vulnerable groups. For the successful establishment of social safety net, the test-bed for evaluation and realization of crime-related research results is required. However, previous R&D test-bed projects such as The Korean Land Specialization Program or U-Eco City project remains only to the stage of verification. Therefore, there are limitedness for realization of result technologies or sustainable operation & management of test-bed after projects finished. So, sustainable operation & management system and guideline of test-bed are necessary. Therefore, this study reviews the strengths and weaknesses of existing test-bed cases and intelligent security researches. After reviewing, the concept of a Intelligent Security Test-bed is established and appropriate test-bed selection criteria is also suggested. Based on objective criteria, selected test-bed can achieve sustainable management even after finishing the project and contribute the construction of standard model for citizen's safety.