• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.388-398
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• 2012

In this study, Entropy method and PROMETHEE(Preference Ranking organization METHod for Enrichment Evaluations) which is one of the multi criteria decision making methods are applied to estimate the relative inundation risk ranking of the urban sewer systems. Then, the evaluation factors were selected considering two main items to estimate the inundation risk using Entropy and PROMETHEE. In the first item considering topographical and environmental factor, average elevation, average slope, width of area, population, density of conduit were selected as the detailed factors of first item which have influence of the overflow occurrence and damage scale in urban sewer system. And, the relative reliability of sewer network was considered as the second item which can quantify the inundation appearance. Then, the reliability is estimated considering the number of overflow nodes and overflow volume simultaneously. Therefore, the suggested inundation risk evaluation method can be used as the evaluation index for sewer networks and contribute to decision making for the sewer rehabilitation policy.

• The Korean Journal of Applied Statistics
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• v.30 no.6
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• pp.1015-1025
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• 2017

Bayesian personalized ranking (BPR) is a state-of-the-art recommendation system techniques for implicit feedback data. Unfortunately, there might be a loss of information because the BPR model considers only the binary transformation of implicit feedback that is non-binary data in most cases. We propose a modified BPR method using a level of confidence based on the size or strength of implicit feedback to overcome this limitation. The proposed method is useful because it still has a structure of interpretable models for underlying personalized ranking i.e., personal pairwise preferences as in the BPR and that it is capable to reflect a numerical size or the strength of implicit feedback. We propose a computation algorithm based on stochastic gradient descent for the numerical implementation of our proposal. Furthermore, we also show the usefulness of our proposed method compared to ordinary BPR via an analysis of steam video games data.

• Journal of Internet Computing and Services
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• v.17 no.3
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• pp.87-93
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• 2016

In the current information-based society, information and communication technology(ICT) is very important for an individual, a society, and a nation. Especially, for a nation, ICT-related industries are forming an important part of a nation's economy. Also, unlike other industries, ICT-related industries do not require various infrastructures, and have an advantage of being developed with a few talented persons in a short period of time. In this sense, identification and education of gifted children in IT become an essential task of a nation's future. In the past, selection of the gifted children was based on paper tests. However, paper tests incurred various side effects such as private education. Since 2013, observation-recommendation system instead of paper tests has been fully adopted. The purpose of this paper is to analyze the validity of observation-recommendation admission system of the gifted children in IT. For this research purpose, the gifted children in gifted science education center attached in a university at Seoul become the focus of the samples. Their entrance score ranking and graduation record raking are compared for analysis of validity of admission system. After statistical analysis, there is a meaningful correlation between entrance score ranking and graduation record ranking for the gifted children in IT. It means that the higher entrance score ranking, the higher graduation record ranking. The analysis results are expected to be valuable baseline data for deciding usefulness of observation-recommendation admission system.

• Journal of Soil and Groundwater Environment
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• v.13 no.6
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• pp.62-71
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• 2008

Soil quality standards (SQS) are necessary to protect the human health and soil biota from the exposure to soil pollutants. The current SQS in Korea contain only sixteen substances, and it is scheduled to expand the number of substances. Chemical ranking and scoring (CRS) system is very effective to screen the priority chemicals for the future SQS in terms of their toxicity and exposure potential. In this study, several CRS systems were extensively compared to propose the assessment factors that required for the screening of soil pollutants The CRS systems considered in this study include the CHEMS-1 (Chemical Hazard Evaluation for Management Strategies), SCRAM (Scoring and Ranking Assessment Model), EURAM (European Union Risk Ranking Method), ARET (Accelerated Reduction/Elimination of Toxics), CRSKorea, and other systems. The additional assessment factors of CRS suitable for soil pollutants were suggested. We suggest soil adsorption factor as an appropriate factor of CRS system to consider chemical transport from soil to groundwater. Other factors such as soil emission rate and cases of accident of soil pollutants were included. These results were reflected to screen the priority chemicals in Korea, as a part of the project entitled ‘Setting the Priority of Soil Contaminants'.

• Journal of the Korean Society of Costume
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• v.63 no.8
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• pp.171-187
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• 2013

This is a study on the military costumes of Hunryeondogam, which was the center of Five Military Camps in the mid and the late Joseon dynasty. I confirmed the characteristics and system of military costumes of Hunryeondogam by document research and positive research. The military organization of Hunryeondogam was comprised of the high-ranking military officers such as Hunryeondaejang, Junggun, Cheonchong, Byeoljang and Gukbyeoljang, the mid and low ranking military officers such as Pachong, Chogwa and soldiers. And the military costume of Hunryeondogam included Gapju, Yoongbok and Goonbok for military officers and all kinds of military uniforms for soldiers. Imjin war and ritualized military ceremonies in the era of peace had influence on the military costume. Officers, for example, were wearing Dangap and soldiers were wearing Cheolgap or Pigap that depended on the branch of the army. Politically, kings in the mid and the late Joseon had organized military organizations to strengthen their royal authority. I think that the policy can be effectively seen by observing the military costume system. The qualitative differences in cloth materials and the presence or absence of patterns of Goonbok, the qualitative differences in the decoration of Jeonrip and the presence or absence of Yodae were able to distinguish the identity and the rank. An assumption can be made that these things could have been affected by social causes, such as frequent trips of the King and stable society. This cause could be influence on substitute Yoongbok with Goonbok that from the low ranking military officers to the high ranking military officers of Hunryeondogam. The societal changes in the mid and the late Joseon dynasty are reflected on the military costumes system of Hunryeondogam.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.129-135
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• 2018

For efficiently safety management of city gas pipelines, the City-gas Pipeline Management System(CPMS) has been developed to systematically manage and analyze the data collected from 33 city gas companies and to effectively perform internal and external affairs related to gas safety management. The piping information data uploaded to the CPMS is ranked the risk according to the criteria specified in the KGS Code, and the safety management of the piping has performed close inspection according to the risk ranking. However, the criteria for deriving the risk ranking is very simple and lacks relevant grounds, and the reliability for the determination of the close inspection pipeline is no high due to the redundant rank. Therefore, we developed a risk assessment program based on the Reliability Based Design Assessment(RBDA) methodology and tried to derive a reasonable risk ranking by linking it with the CPMS system.

• Nuclear Engineering and Technology
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• v.36 no.5
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• pp.388-402
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• 2004

A phenomena identification and ranking table(PIRT) was developed for a main steam line break (MSLB) event for the Advanced Power Reactor-1400 (APR-1400). The selectee event was a double-ended steam line break at full power, with the reactor coolant pump running. The developmental panel selected the fuel performance as the primary safety criterion during the ranking process. The plant design data, the results of the APR-1400 safety analysis, and the results of an additional best-estimate analysis by the MARS computer code were used in the development of the PIRT. The period of the transient was composed of three phases: pre-trip, rapid cool-down, and safety injection. Based on the relative importance to the primary evaluation criterion, the ranking of each system, component, and phenomenon/process was performed for each time phase. Finally, the knowledge-level for each important process for certain components was ranked in terms of existing knowledge. The PIRT can be used as a guide for planning cost-effective experimental programs and for code development efforts, especially for the quantification of those processes and/or phenomena that are highly important, but not well understood.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4408-4425
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• 2023

Alarm flood due to abnormality propagation is the most difficult alarm overloading problem in nuclear power plants (NPPs). Root-cause analysis is suggested to help operators in understand emergency events and plant status. Multilevel Flow Modeling (MFM) has been extensively applied in alarm management by virtue of the capability of explaining causal dependencies among alarms. However, there has never been a technique that can identify the actual root cause for complex alarm situations. This paper presents an automated root-cause analysis system based on MFM. The causal reasoning algorithm is first applied to identify several possible root causes that can lead to massive alarms. A novel root-cause ranking algorithm can subsequently be used to isolate the most likely faults from the other root-cause candidates. The proposed method is validated on a pressurized water reactor (PWR) simulator at HAMMLAB. The results show that the actual root cause is accurately identified for every tested operating scenario. The automation of root-cause identification and ranking affords the opportunity of real-time alarm analysis. It is believed that the study can further improve the situation awareness of operators in the alarm flooding situation.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.100-106
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• 1997

The purpose of this study is to measure perceived joint discomfort in the seated and standing position, and to provide a ranking system of joint discomfort measured in this study. Seven male subjects with no history of musculo-skeletal disorders participated in the experiment. Their physical characteristics were: age -$27.6 {\pm}1.8$ years, stature -$171.0 {\pm}5.5cm$, and body weight -$66.4{\pm}9.3kg$. The results showed that perceived joint discomfort was different depending on the human body joints involved in motion and their movement directions, which imply that the human body motions should be classified intoseveral distinct classes that need to be assigned different weights of postural stress. In the seated postion, the hip movement was the most stressful, the back was the second, and the shoulder was the third. Similarly, in standing postures, the hip was given the highest ranking, followed by the back, and the wrist.

• Proceedings of the KIEE Conference
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• 2000.07e
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• pp.95-98
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• 2000

This paper presents a technique for contingency ranking using line capacity calculation method and outage distribution factors (LODF) which are established by generation shift distribution factors from DC load flow solutions. By using the LODF, the line flow can be calculated a ccording to the modification of base load flow if the contingency occur. To obtain contingency ranking, maximum power tansferred to the load is obtained when load impedance $Z_r$ equal to line impedance $Z_s$. The proposed algorithm has been validated in tests on a 6-bus test system.