• Bulletin of the Korean Mathematical Society
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• v.33 no.3
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• pp.335-342
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• 1996

Suppose $k$ is a field and $M$ is the set of all $m \times n$ matrices over $k$. If T is a linear operator on $M$ and f is a function defined on $M$, then T preserves f if f(T(A)) = f(A) for all $A \in M$.

• Korean Security Journal
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• no.5
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• pp.71-88
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• 2002

This research is aimed to clarify police officer's working personality characteristics. The sample was divide in two sub-groups according to research group of career police officer and comparative group of novice police officer. The followings are list of significant tendencies. First, career police officer have aggression, cynicisms, suspicion contrast to novice police officer. Second, working personalities of aggression, cynicisms, suspicion is relationship between age, rank, service term. Findings of this study is that working personality of police officer in korea was made survey empirically, and identified change process of police officer's working personality.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.9
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• pp.95-101
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• 2000

This paper proposes a general structure observer and shows the characteristic of external noise reduction in linear discrete system. First we propose a simple genera structured observer which includes high gain term or PI(proportional integral) term to eatimate the states of system and show that the observer can estimate the states of system even if an external noise is added to the system's output. An existence condition of the observer is derived and checked by system's rank condition. Through a numerical example we can verify that the proposed observer is effective to estimate the state of system with external noise compared to that of conventional high gain observer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.7
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• pp.723-731
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• 2016

A core technological base to provide enhanced data rates required by 5G mobile wireless communications is the improved bandwidth efficiency using massive multiple-input multiple-output (MIMO) transmission. MIMO transmission requires the channel estimation using the channel state information reference signaling (CSI-RS) and appropriate beamforming, thus the design of the codebook defining proper beamforming vectors is an important issue. In this paper, we propose a multi-rank codebook based on the discrete Fourier transform (DFT) matrix, by utilizing statistical properties of the channel generated by the spatial channel model (SCM). The proposed method includes a structural change of the precoding matrix indicator (PMI) by considering the phase difference distributions between adjacent antenna elements, as well as the selected codevector characteristics of each transmission layer. Performance gain of the proposed method is evaluated and verified by making the performance comparison to the 3GPP standard codebooks adopted by Long-Term Evolution (LTE) systems.

• Journal of Oral Medicine and Pain
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• v.19 no.2
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• pp.169-180
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• 1994

The aim of this study was to compare pain descriptions in common dental patients with those in patients with Temporomandibular disorders(TMDs). The study sample consisted of 104 common dental patients and 74 patients with TMDs, and their chief complaint was pain, Subjects were classified common dental pain group and TMDs pain group, respectively. All the subjects completed Korean Pain Rating Scale(KPRS) on first visit. KPRS contains 90 pain terms, which divided into 20 subclasses in 3 dimensions. Each subclass contains 3-6 pain terms. each patient had chosen only one term from each subclass. If there was no proper term, subject could pass the subclass without completion. Words chosen were categorized into sensory, affective, miscellaneous and total dimension. Thereafter they were processed and analyzed by SPSS/PC+ statistical package program with respect to rank values, scale values, number of words chosen and frequency of each subclass. The obtained results of this study were as follows : 1. Total mean number of words chosen was 7.6. 2. Chronic patients groups with Temporomandibular disorders had chosen more freuently from the subclasses in affective dimension than the patients in acute common dental pain group. 3. Frequency of affective dimension was higher in chronic patients groups with Temporomandibular disorders than that of acute patients group with Temporomandibular disorders. 4. Chronic patients group with Temporomandibular disorders had higher frequency in constrictive pressure pain, traction pressure pain, dull pain and fatigue-related pain terms than acute common dental patients group. 5. Acute patients group with Temporomandibular disorders had higher frequency in traction pressure pain and dull pain terms but had lower frequency in chemical pain, peripheral nerve pain and cold pain terms than acute common dental patients groups. 6. There were high positive correlation between the scale- and rank-value in the pain rating index.

• Journal of Labour Economics
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• v.26 no.2
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• pp.61-95
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• 2003

This paper investigates the characteristics of Japanese vocational education and training(VET) system and its recent changes with regard to the labour market changes under the long-term economic depression. The employment system model of Marsden(1999) is used as an analytical framework. By the review of 'the debate of intellectual skill', it is pointed out that the fundamental characteristic of Japanese VET system lies in forming multi-functional workers by the internal promotion in connection with the OJT-focused enterprise training along the job-competency rank system. In this system 'the skill as work-competency' is not institutionalised. By the long-term depression this type of internal labour market (ILM) has been under serious changes. By the policy analyses it is made clear that the direction of its change is not toward the collapse of the ILM. A series of labor market and VET policies does aim at sustaining the ILM by the introduction of the unified job qualification system, which is expected to institutionalise the widening external labour market into the craft-based labour market.

• Journal of KIISE:Software and Applications
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• v.33 no.8
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• pp.718-729
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• 2006

There has been increasing interest in automatic term recognition (ATR), which recognizes technical terms for given domain specific texts. ATR is composed of 'term extraction', which extracts candidates of technical terms and 'term selection' which decides whether terms in a term list derived from 'term extraction' are technical terms or not. 'term selection' is a process to rank a term list depending on features of technical term and to find the boundary between technical term and general term. The previous works just use statistical features of terms for 'term selection'. However, there are limitations on effectively selecting technical terms among a term list using the statistical feature. The objective of this paper is to find effective features for 'term selection' by considering various aspects of technical terms. In order to solve the ranking problem, we derive various features of technical terms and combine the features using machine-learning algorithms. For solving the boundary finding problem, we define it as a binary classification problem which classifies a term in a term list into technical term and general term. Experiments show that our method records 78-86% precision and 87%-90% recall in boundary finding, and 89%-92% 11-point precision in ranking. Moreover, our method shows higher performance than the previous work's about 26% in maximum.

• Journal of the Korean Society for information Management
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• v.13 no.1
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• pp.205-226
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• 1996

Under the hypothesis that any pair of terms in the sentence is meaningful to present the context of the paper, the Brillouin measure of term relatedness in automatic indexing is proposed. For the experiment, the pair of terms simul-taneously appeared in two or more sentences of the paper are extracted from the title and abstract of the paper. Com-pared with the list of index terms or subject headings suggested by the author, the terms in term relatedness graph are highly matched with the terms in the list. Especially, it is revealed that the rank of terms by synthetic strength is use-ful in the selection of index terms.

• International Journal of Knowledge Content Development & Technology
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• v.9 no.3
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• pp.23-41
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• 2019

This study combines the concept of degree centrality in complex network with the Term Frequency $^*$ Proportional Document Frequency ($TF^*PDF$) algorithm; the combined method, called PMCN (PDF-Modified similarity and Complex Network), constructs relationship networks among sentences for writing news summaries. The PMCN method is a multi-document summarization extension of the ideas of Bun and Ishizuka (2002), who first published the $TF^*PDF$ algorithm for detecting hot topics. In their $TF^*PDF$ algorithm, Bun and Ishizuka defined the publisher of a news item as its channel. If the PDF weight of a term is higher than the weights of other terms, then the term is hotter than the other terms. However, this study attempts to develop summaries for news items. Because the $TF^*PDF$ algorithm summarizes daily news, PMCN replaces the concept of "channel" with "the date of the news event", and uses the resulting chronicle ordering for a multi-document summarization algorithm, of which the F-measure scores were 0.042 and 0.051 higher than LexRank for the famous d30001t and d30003t tasks, respectively.

• Journal of the Korean Operations Research and Management Science Society
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• v.42 no.3
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• pp.35-49
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• 2017

The main objective of this paper is to empirically analyze the efficiency effects of mergers on Korean pharmaceutical firms and suggests managerial or policy implications for managers or policy makers. This study selects non-merging control firms close to the size of merging firms, as well as a set of merging firms, and measures the effects of mergers on efficiency three years before and after the merger using the non-parametric data envelopment analysis (DEA) method. To compare the differences of efficiency means among several groups, Wilcoxon rank sum test or Wilcoxon signed rank test is used. It showed that the long-term effects after the merger appeared partially. Furthermore, it was observed that there was no difference statistically in the efficiency between merging and non-merging firms. Also, there was no difference statistically in the efficiency between the pre- and post-merger periods. In conclusion, there was not any observed synergy effect through group (or affiliated) mergers between affiliates or related mergers for Korean pharmaceutical firms.