• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.287-296
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• 2017

Although emission regulations have been gradually strengthened in the past decade, the road transport section remains the most important source of NOx emission in air pollution. One reason is that there has been an increase in the proportion of diesel vehicles and in the volume of traffic. In addition, the certification procedure for standard emission limit does not sufficiently reflect real traffic condition and various driving patterns. Therefore, the European Commission(EC) has recently come up with the RDE-LDV(Real driving emissions-light duty vehicle) regulations, and the Ministry of Environment in Korea has been conducting research on evaluating RDE-LDV with PEMS(Portable Emission Measurement Systems). According to the trip requirements of the 2nd RDE package announced by the EC, the objectives of the present study include the development of Korean RDE routes to reflect domestic traffic and road conditions. Based on the results, both RDE routes are in correct compliance with RDE-LDV regulations, including trip requirements and trip dynamics. KOR-NIER Route 1, in particular, has a higher driving load in rural driving with regard to excessive gradient of elevation compared to KOR-NIER Route 2, including relatively plane rural driving.

• Nuclear Engineering and Technology
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• v.46 no.2
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• pp.235-246
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• 2014

The automatic seismic trip system (ASTS) continuously monitors PGA (peak ground acceleration) from the seismic wave, and automatically generates a trip signal. This work presents how the system can be designed by using a systems engineering approach under the given regulatory criteria. Overall design stages, from the needs analysis to design verification, have been executed under the defined processes and activities. Moreover, this work contributes two significant design areas for digitalized ASTS. These are firstly, how to categorize the ASTS if the ASTS has a backed up function of the manual reactor trip, and secondly, how to set the requirements using the given design practices either in overseas ASTS design or similar design. In addition, the methodology for determining the setpoint can be applied to the I&C design and development project which needs to justify the error sources correctly. The systematic approach that has been developed and realized in this work can be utilized in designing new I&C (instrument and control system) as well.

• Nuclear Engineering and Technology
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• v.27 no.2
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• pp.203-215
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• 1995

A continued operation of RCPs during a certain small break LOCA may increase unnecessary inventory loss from the RCS causing a severe core uncovery which might lead to a fuel failure. After TMI-2 accident, the CEOG developed RCP trip strategy called “Trip-Two/Leave-Two” (T2/L2) in response to NRC requests and incorporated it in the generic EPG for CE plants. The T2/L2 RCP trip strategy consists of tripping the first two RCPs on low RCS pressure and then tripping the remaining two RCPs if a LOCA has occurred. This analysis determines the RCP trip setpoint and demonstrates the safe operational aspects of RCP trip strategy during a small break LOCA for YGN 3&4. The trip setpoint of the first too RCPs for YGN 3&4 is calculated to be 1775 psia in pressurizer pressure based on the limiting small break LOCA with 0.15 ft$^2$ break size in the hot leg. The analysis results show that YGN 3&4 can maintain the core coolability even if the operator fails to trip the second too RCPs or trips at worst time. Also, the YGN 3&4 RCP trip strategy demonstrates that both the 10 CFR 50.46 requirements on PCT and the ANSI standards 58.8 requirements on operator action time can be satisfied with enough margin. Therefore, it is concluded that the T2/L2 RCP trip strategy with a trip setpoint of 1775 psia for YGN 3&4 can provide improved operator guidance for the RCP operation during accidents.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1281-1284
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• 2015

Multi-day trip itinerary planning is complex and time consuming task, from selecting a list of worth visiting POIs to arranging them into an itinerary with various constraints and requirements. In this paper, we present CYTRIP, a multi-day trip itinerary planning system that engages human computation (i.e. crowd recommendation) to collaboratively recommend POIs by providing a shared workspace. CYTRIP takes input the collective intelligence of crowd (i.e. recommended POIs) to build a multi-day trip itinerary taking into account user's preferences, various time constraints and locations. Furthermore, we explain how we engage crowd in our system. The planning problem and domain are formulated as AI planning using PDDL3. The preliminary empirical experiments show that our domain formulation is applicable to both single-day and multi-day trip planning.

• Journal of KIISE:Software and Applications
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• v.32 no.2
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• pp.108-118
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• 2005

The software of the nuclear power plant digital control system is a safety-critical system where many techniques must be applied to it in order to preserve safety in the whole system. Formal specifications especially allow the system to be clearly and completely specified in the early requirements specification phase, therefore making it a trusted method for increasing safety. In this paper, we discuss a systematic method, which generates PLC-based FBD programs from the requirements specification using NuSCR, a formal requirements specification method. This FBD programs takes an important position in design specification. The proposed method can reduce the possible errors occur in the manual design specification, and the software development cost and time. To investigate the usefulness of our proposed method, we introduce the fixed set-point rising trip example, a trip logic of BP in DPPS RPS, which is presently being developed at KNICS.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.371-373
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• 2001

Main functions of Generator Circuit Breaker(GCB) is cut the generator off from the main transformers and the aux. transformers when plant trip or startup. In this paper, the design requirements For GCB of nuclear power plant is examined. NRC presented the area of review, acceptance criteria and review procedures of GCB in the SRP(Standard Review Plan). In Korea, APR1400 adapted the GCB in main power system.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.463-478
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• 2019

The most important non-functional requirements for dependability of any Embedded Real-Time Safety Systems are safety, availability and reliability requirements. System architecture plays the primary role in achieving these requirements. Compliance with these non-functional requirements should be ensured early in the development cycle with appropriate considerations during architectural design. In this paper, we present an application of system architecture modeling for quantitative assessment of system dependability. We use probabilistic model checker (PRISM), for dependability analysis of the DTMC model derived from system architecture model. In general, the model checking techniques do not scale well for analyzing large systems, because of prohibitively large state space. It limits the use of model checking techniques in analyzing the systems of practical interest. We propose abstraction based compositional analysis methodology to circumvent this limitation. The effectiveness of the proposed methodology has been demonstrated using the case study involving the dependability analysis of safety system of a large Pressurized Water Reactor (PWR).

• The Journal of Fisheries Business Administration
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• v.39 no.2
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• pp.41-60
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• 2008

This study is basically to investigate the possibility of revitalizing the fishing village economy by targeting on trip type, propensity, and awareness of visitors who visited Gogunsan in JeonBuk by applying Blue Amenity. As the result of survey, it showed that visitors in Gosunsan islands generally were satisfied with trip, and they had considerably higher intention of revisit. However, it showed that the improvement and publicity of various travel services including resources and facilities were demanded. In particular, it should pay attention to requirements depending on age and selection of main visitors with reference to revisit, and as the result, the factors having the most important influence on are traffic, and natural scenery, so it is considered that these factors must be maintained to increase the rate of revisit with full of concentration. Besides, it is confirmed that Visitors are unfamiliar with Blue Amenity applying fishing village's own historical cultural resources with reference to preferring islands trip, and they were much concerned about the establishment of tentatively named "regional(urban - fishing village) center" to revitalize the fishing village economy. Moreover it could grasp the tourist industry operated jointly by fishing villages, the pride of town to characterize, advantage in promoting the tourist industry as compared with other regions, and difficulties or recommendations in promoting the tourist industry. And comprehensive investigation of Blue Amenity resources in this region and the measures of improving life environment must be performed in future.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.13 no.1
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• pp.9-19
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• 2005

Airplane fuel takes large portion of airline operation cost and recently it has been grown up to about 25% of operating cost. So airlines are making efforts to reduce fuel consumption continuously and also aircraft manufacturers are making efforts to develop less fuel-consuming engines but it takes great expenses and times to develop such engines. In this study, fuel requirements of FAR and JAR, especially contingency fuel requirements, are compared and the effectiveness of each method is analyzed.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.3
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• pp.25-38
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• 2023

Instrumentation and control systems measure and control various variables of nuclear facilities to operate nuclear power plants safely. A diverse protection system, a representative instrumentation and control system, generates a reactor trip and turbine trip signal by high pressure in a pressurizer and containment to satisfy the design requirements 10CFR50.62. Also, it generates an auxiliary feedwater actuation signal by low water levels in steam generators. Cybersecurity has become more critical as digital technology is gradually applied to solve problems such as performance degradation due to aging of analog equipment, increased maintenance costs, and product discontinuation. This paper analyzed possible cybersecurity threat scenarios in the diverse protection system using attack trees. Based on the analyzed cybersecurity threat scenario, we calculated the probability of attack occurrence and confirmed the cybersecurity risk in connection with the asset value.