• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.161-172
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• 2005

This study is to develop Bus Transit Route Analysis and Evaluation Model that can product the quantitative performance measures for Bus Transit Route Network Design. So far, in Korea, there are no so many models that evaluate a variety of other performance measures or service quality that are of concern to both the transit users and operator because of lower-level bus database system and transit route network analysis algorithm's limit. The BTRAEM in this research differ from the previous approach in that the BTRAEM employs a multiple path transit trip assignment model that explicitly considers the transfer and different travel time after boarding. And we develop input-output data structure and quantitative performance measure for the BTRAEM. In the numerical experimental applying BTRAEM to Mandl transit network, We got the meaningful results on performance measure of bus transit route network. In the future, we expect BTRAEM to give a good solution in real transit network.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2534-2546
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• 2021

Nuclear emergency preparedness and response is an essential part to ensure the safety of nuclear power plant (NPP). Key support technologies of nuclear emergency decision-making usually consist of accident diagnosis, source term estimation, accident consequence assessment, and protective action recommendation. Source term estimation is almost the most difficult part among them. For example, bad communication, incomplete information, as well as complicated accident scenario make it hard to determine the reactor status and estimate the source term timely in the Fukushima accident. Subsequently, it leads to the hard decision on how to take appropriate emergency response actions. Hence, this paper aims to develop a method for rapid source term estimation to support nuclear emergency decision making in pressurized water reactor NPP. The method aims to make our knowledge on NPP provide better support nuclear emergency. Firstly, this paper studies how to build a Bayesian network model for the NPP based on professional knowledge and engineering knowledge. This paper presents a method transforming the PRA model (event trees and fault trees) into a corresponding Bayesian network model. To solve the problem that some physical phenomena which are modeled as pivotal events in level 2 PRA, cannot find sensors associated directly with their occurrence, a weighted assignment approach based on expert assessment is proposed in this paper. Secondly, the monitoring data of NPP are provided to the Bayesian network model, the real-time status of pivotal events and initiating events can be determined based on the junction tree algorithm. Thirdly, since PRA knowledge can link the accident sequences to the possible release categories, the proposed method is capable to find the most likely release category for the candidate accidents scenarios, namely the source term. The probabilities of possible accident sequences and the source term are calculated. Finally, the prototype software is checked against several sets of accident scenario data which are generated by the simulator of AP1000-NPP, including large loss of coolant accident, loss of main feedwater, main steam line break, and steam generator tube rupture. The results show that the proposed method for rapid source term estimation under nuclear emergency decision making is promising.

• Journal of vocational education research
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• v.36 no.2
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• pp.23-50
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• 2017

The purpose of this study was to determine the hierarchical linear relationship among receptivity to organizational change, individual variables of professors and organizational variables in junior colleges. The population for this study was 12,920 professors in 139 junior colleges. Using random sampling method considering subject, 800 professors in 40 colleges were sampled for this study. The data were collected from May 26 to June 13. A total of 445 out of 800 questionnaires were returned of which 441 of 40 junior colleges were used for analysis after data cleaning. These data were analyzed by both descriptive statistics and One-way ANOVA with Random Effects, Ranmdom-Coefficients Regression Model, and Intercepts-and Slopes-as-Outcomes Model of hierarchical linear model(HLM). All data analysis was accomplished using the SPSS 20.0 for windows program and the HLM 6.0 for windows program. An alpha level of 0.05 was established priori for determining the significance. The findings of the study were as follows: First, the level of receptivity to organizational change of professions in junior college was 3.94. Second, 56.5% of total variance in receptivity to organizational change was individual level variance. 43.5% of total variance in receptivity to organizational change was organizational level variance. Third, personal valence about organizational change, psychological ownership, experience of assignment, years of service and job security had positive effects on receptivity to organizational change while years of service had negative effects on receptivity to organizational change. The effect of personal valence about organizational change was highest, and the effect of job security was lowest. Fourth, degree of organizational change, participative decision-making, group culture and accessibility of information related to organizational change had positive effects on receptivity to organizational change. The effect of degree of organizational change was highest, and the effect of accessibility of information related to organizational change was lowest.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.82-82
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• 2010

We measure the topology of the galaxy distribution using the Seventh Data Release of the Sloan Digital Sky Survey (SDSS DR7), examining the dependence of galaxy clustering topology on galaxy properties. The observational results are used to test galaxy formation models. A volume-limited sample defined by Mr<-20.19 enables us to measure the genus curve with amplitude of G=378 at 6h-1Mpc smoothing scale, with 4.8% uncertainty including all systematics and cosmic variance. The clustering topology over the smoothing length interval from 6 to 10h-1Mpc reveals a mild scale-dependence for the shift and void abundance (A_V) parameters of the genus curve. We find strong bias in the topology of galaxy clustering with respect to the predicted topology of the matter distribution, which is also scale-dependent. The luminosity dependence of galaxy clustering topology discovered by Park et al. (2005) is confirmed: the distribution of relatively brighter galaxies shows a greater prevalence of isolated clusters and more percolated voids. We find that galaxy clustering topology depends also on morphology and color. Even though early (late)-type galaxies show topology similar to that of red (blue) galaxies, the morphology dependence of topology is not identical to the color dependence. In particular, the void abundance parameter A_V depends on morphology more strongly than on color. We test five galaxy assignment schemes applied to cosmological N-body simulations to generate mock galaxies: the Halo-Galaxy one-to-one Correspondence (HGC) model, the Halo Occupation Distribution (HOD) model, and three implementations of Semi-Analytic Models (SAMs). None of the models reproduces all aspects of the observed clustering topology; the deviations vary from one model to another but include statistically significant discrepancies in the abundance of isolated voids or isolated clusters and the amplitude and overall shift of the genus curve. SAM predictions of the topology color-dependence are usually correct in sign but incorrect in magnitude.

• Journal of Korea Trade
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• v.24 no.8
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• pp.153-170
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• 2020

Purpose - As the US-China trade war intensifies and lasts long time, there is growing concern about its potential effects on the global economy. In particular, for the countries like Korea that have a large economic dependence on the economy of the two countries, the US-China trade war may have a great repercussion in many ways. The aim of this paper is to investigate the global productivity and market structure implications of the US-China trade war for Korea, as well as for other surrounding countries and regions. Design/methodology - In this paper, we develop a full multi-country/region multi-sector computable general equilibrium (CGE) model of global trade incorporating heterogeneous workers and firms in individual skill levels and used technologies. We then calibrate the model using a global Social Accounting Matrix (SAM) dataset extracted from the recently released GTAP 10 Database, and assess the potential effects of the US-China trade war on the aggregate real productivity and the market structure for Korea, as well as for other surrounding countries and regions. Findings - We show that the US-China trade war may largely affect the aggregate productivity in each sector in each country/region, as well as the global market structure through entry and exit of firms, which results finally in considerable changes in the industrial comparative advantage of each country/region. Though the effects are diverse sector by sector, the results show that Korea may also be affected significantly: concerning the real productivity implications, it is shown that the machinery industry may be affected the most negatively; on the other hand, it is shown that the number of exporting firms may decrease the most in the other transports industry. Originality/value - As the US-China trade war intensifies, many studies have tried to estimate the possible implications, and for this usually the CGE models have largely been used as the standard tool for evaluating the impacts of changes in trade policies. Standard CGE models, however, cannot be used to assess the global productivity and market structure implications due to the symmetric and simplified base assumptions. This paper is the first to analyze and quantify the possible impacts of the US-China trade war on the aggregate productivity and global market structure using a CGE model incorporating endogenous skill-technology assignment of heterogeneous workers and firms.

• The Korean Journal of Archival Studies
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• no.77
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• pp.151-187
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• 2023

The cooperation between archives and libraries is necessary for the management of limited operational space and the improvement of work efficiency. "Larchive" is one of the model of cooperation between libraries and archives, so it can be an alternative plan for institutions that face difficulties in collaborating through "Larchiveum" - growing model of cooperation between libraries, archives, and museums. This study presents the recognition of Larchive to university archivists and librarians, and suggests a practical operation plan for cooperation between the archive and library. As a result, "Larchive" was relatively less aware of archivists and librarians, but in the practical point of view, respondents were fully aware of the need for cooperation between archives and libraries. In particular, Larchive was presented as a rational alternative model for both of the groups. And the need for material cooperation can be confirmed through the recognition survey, and the improvement plan for business cooperation can be confirmed through the FGI. Some prerequisites are proposed such as securing a collaborative workplace, assignment of budget and manpower. Through the results, this study presented practical operational plans for organizational cooperation in the form of Larchive, focusing on the perspectives of "teaching and learning support", "research support services", "curation services", "collection and management of school history data", "cooperation for evaluation", and drew discussion points.

• Korean Security Journal
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• no.6
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• pp.47-65
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• 2003

In Korea, Private security companies has steadily grown and amounts to 2,051 places as of November 30, 2002. Private security in korea is carrying out firm name role assignment to have held the police and public peace environment change factors for a standard faithfully, and protects social a little property that is a basic purpose, and it is spare no efforts in loss prevention. In spite of numeral increase of private security companies, private security companies have many problem. Moreover, they mostly did not have any remarkable in-house expertises in their own business under tough conditions. Under the unfavorable circumstances including insufficient investment and education in private security guard, there have been actually little further studies on private security business in practices. So this study mainly focused on addressing the installation security business managed by authorized companies, which amount to 96%(1,963 companies) of total 2,051 domestic security companies. Furthermore, the study formulated and modeled a series of business procedures in private security companies. A series of business procedures of private security companies can be modeled as follows : Setting of a business scope and aim market ${\Rightarrow}$ Marketing, Contact from customers(On-line or Off-line) ${\Rightarrow}$ Diagnosis of security target ${\Rightarrow}$ Submission of security operational plan ${\Rightarrow}$ Estimation of security operational plan ${\cdot}$ decision ${\Rightarrow}$ Contract ${\Rightarrow}$ Employment, selection of security guards ${\Rightarrow}$ Nomination of security guard instructors ${\Rightarrow}$ Education & training of security guards ${\Rightarrow}$ subscribe to insurance of damage liability ${\Rightarrow}$ Commitment and placement of security guards ${\Rightarrow}$ Establishment and preparation of security planning ${\Rightarrow}$ Field management and procurement of relevant security service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.7
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• pp.989-998
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• 1993

In a bursty user traffic mode, ALOHA random multiple access protocol achieves higher performance than any conventional fixed assignment technique. One of central problems in slotted ALOHA is synchronization. Because of the long propagation delay in satellite mobile communication, packet may be spilt over into adjacent slots and thus guard time may be included between packet intervals. In conventional ALOHA channels, simultaneous transmission by two or more users results in a collision : the unsuccessful packets have to be retransmitted according to some retransmission algorithm. However, in a radio environment, users are often at different distances from the receiver : therefore, their received signals have substantially different power levels. The packet arriving with the highest energy now has a good chance of being detected accurately. Similarly, in some spread-spectrum random access systems, the earliest arriving packet dominates later arriving packets and thus captures the channel. In this paper slotted ALOHA channel with non zero guard time and capture probability is studied. Using the Markovian model, the performance of slotted ALOHA with guard time and capture effects is derived and compared with that of the conventional ALOHA via numerical analysis.

• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.409-418
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• 2004

Multicast services are provided on the Internet in fast increasing . Therefore it is important to keep security for multicast communication. Member leaving is deeply associated with scalability problem for group key management. If one member of the group is removed, new group key has to be generated and distributed to all remaining members of group. Minimizing the number of messages and operation cost for generation of the composite keys are important evaluating criteria of multicast key management scheme since generation and distribution of new keys for rekeying require expensive operation. Batch removal can reduce these important parameters rather than removing members sequentially In fashion one after another. In this paper, Hamming distance is calculated between eve교 members to be removed. The members with Hamming distance less than threshold are selected for rekeying procedure. With running the round assignment algorithm In the case of removing several members simultaneously, our model has advantages of reducing the number of message and operation cost for generation of the composite keys and eliminating possibility of collusion attack for rekeying.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.3
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• pp.205-215
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• 2004

The characteristic ratio assignment (CRA) method〔1〕 is new polynomial approach which allows to directly address the transient responses such as overshoot and speed of response time in time domain specifications. The method is based on the relationships between time response and characteristic ratios($\alpha_i$ ) and generalized time constant (T), which are defined in terms of coefficients of characteristic polynomial. However, even though the CRA can apply to developing a linear controller that meets good transient responses, there are still some fundamental questions to be explored. For the purpose of this, we have analyzed several sensitivities of a linear system with respect to the changes of coefficients itself and $\alpha_i$ of denominator polynomial. They are (i) the unnormalized root sensitivity : to determine how the poles change as $\alpha_i$ changes, and (ii) the function sensitivity to determine the sensitivity of step response to the change of o, and to analyze the sensitivity of frequency response as o, changes. As an other important result, it is shown that, under any fixed T and coefficient of the lowest order of s in denominator, the step response is dominantly affected merely by $\alpha_1, alpha_2 and alpha_3$ regardless of the order of denominator higher than 4. This means that the rest of the$\alpha_i$ s have little effect on the step response. These results provide some useful insight and background theory when we select $\alpha_i$ and T to compose a reference model, and in particular when we design a low order controllers such as PID controller.