• Title/Summary/Keyword: Related variable

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High-School Students' Internet Addiction and Related Variables (중.고등학생의 인터넷 중독과 관련 변인 연구)

  • Jeon, Young-Ja;Seo, Moon-Young
    • Journal of the Korean Home Economics Association
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    • v.44 no.3 s.217
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    • pp.13-25
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    • 2006
  • In the information age, the spread of internet has a lot of positive aspects. However, it also has very serious problems with adverse effects on immature teenagers both physically and mentally. Among them, internet addiction has recently grown into a social problem. The purpose of this study is to examine the relationship between the degree of internet addiction of teenagers and the related variables, such as individual variables, using internet variable, parent-child relationship variable, and psychological variable. The survey subjects were 452 high school students in the Gimhae area. The results were as follows: First, the average score of internet addiction among the teenagers of this study was 48.24 out of 100. Which according to Young's classification, corresponds to an early stage addiction. Second, there was a significant difference in the degree of internet addiction by students' school record. The low-graded group was highly addicted to the internet. Third, the longer the teenagers were exposed to the internet, the higher they were addicted. Fourth, the degree of internet addiction was influenced by parent-child relationship. There was low addiction in a group with their parents' high support. Fifth, the degree of internet addiction was differed by psychological variables, such as self-control, self-esteem and depression. Low self-control, low self-esteem and highly depressed teenagers were related to a higher degree of internet addiction.

Assessing the risk of work-related musculoskeletal disorders in 119 EMT: a focus on patient-carrying tasks (119구급대원의 업무 관련성 근골격계 질환 위험성 평가 : 환자 운반 작업을 중심으로)

  • Jeong-Won Son
    • The Korean Journal of Emergency Medical Services
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    • v.27 no.3
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    • pp.33-46
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    • 2023
  • Purpose: This study aims to evaluate the risk of work-related musculoskeletal disorders (WMSDs) in 119 EMT during patient-carrying tasks using a long backboard (LBB) and a variable stretcher. Methods: Manikins were used as patients, and 45 new 119 EMT from K Fire Academy were filmed performing patient-carrying tasks on stairs. The tasks were analyzed using Ovako working posture analysis system (OWAS) and Rapid entire body assessment (REBA). Results: In using LBB, the OWAS score was Mode 3(Mean 2.37, Maximum 3), requiring as soon as possible corrective action, the REBA score was Mode 11(Mean 9.16, Maximum 11), requiring immediate improvement. In using variable stretcher, the OWAS score was Mode 1(Mean 2.33, Maximum 3), non-necessity for corrective action, the REBA score was Mode 9(Mean 8.0, Maximum 11), requiring as soon as possible. Conclusion: In conclusion, improvement was needed in one task (carrying a patient using a LBB) in the OWAS and in two tasks (carrying a patient using a LBB, carrying a patient using a variable stretcher) in the REBA. Thereby, required attention and management of WMSDs during training. In addition, it is essential to carry out objective and quantitative assessments through ergonomic analysis by occupational health professionals when designing future training programs to prevent WMSDs.

Continuously Variable Transmission Composed of a V-Belt Drive and a 2K-H II Type Differential Cear Unit (V-벨트식 변속장치와 2K-H ll형식 차등기어장치의 복합형 무단변속기)

  • Kim, Yeon-Su;Choi, Sang-Hun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.8
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    • pp.1495-1505
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    • 2002
  • As combining the functions of a 2K-H B type differential gear unit and a V-belt type continuously variable unit(CVU), 16 different mechanisms are presented. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. Continuously variable transmission(CVT) mechanisms are proposed, which can of ffr a backward mode, a geared neutral, an underdrive mode and an overdrive mode. They are not required of a starting device as a torque converter. CVT mechanisms developed here present two distinct operating modes which are a power circulation mode and a power split mode. The transition of two modes takes place at the particular CVU speed ratio. For these CVT mechanisms, performance analysis related to speed ratio, power ratio and theoretical efficiency are executed.

The Effect on Forming Functional Concept by Teaching Function Based on Variable (변수에 의한 함수 지도가 함수개념의 형성에 미치는 효과)

  • 이덕호;길영순
    • Journal of the Korean School Mathematics Society
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    • v.4 no.1
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    • pp.103-114
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    • 2001
  • The purpose of this study is to develop learning materials for functional concept on variable and to verify the effect of how well students could learn functional concept after they studied with those materials. To accomplish the purpose of this study, I developed learning materials and after teaching students with them. I have concluded the followings : First, there was little effect in teaching functional concept on variable between two experimental groups, whereas teaching functional concept had greater effect on forming functional concept in high level groups in those two experimental groups. Second, teaching functional concept on variable had little effect on students' understanding of functional concept and perfecting tables in Black box, graph, and mathematical problems, whereas there was much effect in students' understanding functional concept and solving relation formula, image, and range problems related to everyday life or general things. On the basis of the problems which appeared in the process of this study, the following can be suggested : First, we should develop learning materials fit for low level students so that they could understand functional concept. Second, we should continue to teach the basic problems like solving relation formula, image, and range, and understanding functional concept in graph until students are able to understand them exactly. Third, since the goals of Unit Function in a middle school textbook is to solve problems related to everyday life through functional thinking, there should be change in constructing systematic contents of Unit Function in a middle school textbook.

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The Effect of Related Party Transactions on Crash Risk (특수관계자 거래가 주가급락에 미치는 영향)

  • Ryu, Hae-Young
    • The Journal of Industrial Distribution & Business
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    • v.9 no.6
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    • pp.49-55
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    • 2018
  • Purpose - This paper examines the effect of related party transactions on crash firm-specific stock price crash risk. Ownership of a typical Korean conglomerate is concentrated in a single family. In those entities, management and board positions are often filled by family members. Therefore, a dominant shareholder can benefit from related party transactions. In Korea, firms have to report related party transactions in financial statement footnotes. However, those are not disclosed in detail. The more related party transactions are the greater information risk. Thus, companies with related party transactions are likely to experience stock price crashes. Research design, data, and methodology - 2,598 firm-year observations are used for the main analysis. Those samples are from TS2000 database from 2009 to 2013, and the database covers KOSPI-listed firms in Korea. The proxy for related party transactions (RTP) is calculated by dividing total transactions to the related-party by total sales. A dummy variable is used as a dependent variable (CRASH) in the regression model. Logistic regression is used to explain the relationship between related party transactions and crash risk. Then, the sample was separated into two groups; tunneling firms and propping firms. The relation between related party transactions and crash risk variances with features of the transaction were investigated. Results - Using a sample of KOSPI-listed firms in TS2000 database for the period of 2009-2013, I find that stock price crash risk increases as the trade volume of related-party transactions increases. Specifically, I find that the coefficient of RPT is significantly positive, supporting the prediction. In addition, this relationship is strong and robust in tunneling firms. Conclusions - The results report that firms with related party transactions are more likely to experience stock price crashes. The results mean that related party transactions increase the possibility of future stock price crashes by enlarging information asymmetry between controlling shareholders and minority shareholders. In case of tunneling, it could be seen that related party transactions are positively associated with stock crash risk. The result implies that the characteristic of the transaction influences crash risk. This study is related to a literature that investigates the effect of related party transactions on the stock market.

A Variable Window Method for Three-Dimensional Structure Reconstruction in Stereo Vision (삼차원 구조 복원을 위한 스테레오 비전의 가변윈도우법)

  • 김경범
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.7
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    • pp.138-146
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    • 2003
  • A critical issue in area-based stereo matching lies in selecting a fixed rectangular window size. Previous stereo methods doesn't deal effectively with occluding boundary due to inevitable window-based problems, and so give inaccurate and noisy matching results in areas with steep disparity variations. In this paper, a variable window approach is presented to estimate accurate, detailed and smooth disparities for three-dimensional structure reconstruction. It makes the smoothing of depth discontinuity reduced by evaluating corresponding correlation values and intensity gradient-based similarity in the three-dimensional disparity space. In addition, it investigates maximum connected match candidate points and then devise the novel arbitrarily shaped variable window representative of a same disparity to treat with disparity variations of various structure shapes. We demonstrate the performance of the proposed variable window method with synthetic images, and show how our results improve on those of closely related techniques for accuracy, robustness, matching density and computing speed.

A study on the effects of environmental investment and costs on environmental performance (환경 투자 및 비용이 기업의 환경성과에 미치는 영향)

  • Park, Gwang-Dueg;Park, No-Suk;Kim, Seong-Su;Seo, In-Seok
    • Journal of Korean Society of Water and Wastewater
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    • v.23 no.3
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    • pp.315-320
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    • 2009
  • This study found that introduction of environmental systems and increased environmental investment have a major impact on K company's sustainable development. The analysis indicated that the environmental investment variable has a close relationship with production quantity, sales, and the amount of sludge treatment variables in K company. However, all other variables including the cost of disinfection chemicals, and the expenditure of sludge treatment have no relationship with the environmental investment variable. Additionally, short-term results show that the company's environmental expenditure variable is conversely related with the environmental performance variable.

Gene Expression Pattern Analysis via Latent Variable Models Coupled with Topographic Clustering

  • Chang, Jeong-Ho;Chi, Sung Wook;Zhang, Byoung Tak
    • Genomics & Informatics
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    • v.1 no.1
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    • pp.32-39
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    • 2003
  • We present a latent variable model-based approach to the analysis of gene expression patterns, coupled with topographic clustering. Aspect model, a latent variable model for dyadic data, is applied to extract latent patterns underlying complex variations of gene expression levels. Then a topographic clustering is performed to find coherent groups of genes, based on the extracted latent patterns as well as individual gene expression behaviors. Applied to cell cycle­regulated genes of the yeast Saccharomyces cerevisiae, the proposed method could discover biologically meaningful patterns related with characteristic expression behavior in particular cell cycle phases. In addition, the display of the variation in the composition of these latent patterns on the cluster map provided more facilitated interpretation of the resulting cluster structure. From this, we argue that latent variable models, coupled with topographic clustering, are a promising tool for explorative analysis of gene expression data.

Automatic control problems of VVVF converter-based variable-frequency type air (VVVF기를 기초한 가변식기압급수설비의 자동제어 문제)

  • 박용규
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.468-468
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    • 1991
  • The variable-frequency type water supply equipment, which adopts the variable-voltage and variable-frequency converter(VVVF converter) to govern automatically the rotating speed of a pump, can save 15-20% of power, as compared with a throttle-controlled pump device or an airpressurized water supply equipment, and is finding a wide application. However, it still has some disadvantages : greater pressure fluctuations during switching over the pump and prolonged low-effeciency running of the pump in the case of small consumption of water. Therefore, it is difficult to apply the equipment to the fire water supply system where the water should not be put into use unless a fire takes place, and the water pressure in pipelines should permanently remain constant. This paper introduces the automatic regulation principle of the variable-frequency type air-pressurized water supply equipment (hereafter referred to as simply BFQS equipment) for dual purposes of daily life and fire control, which combined both technologies of speed governing by a converter and air-pressurized water supplying, then discusses some problems related to automatic control, and finally gives the experimental results of an embodiment-BPQS-100-50 water supply equipment.

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Economic Design of a Two-Sided Two-Stage Screening Procedure with a Prescribed Outgoing Quality

  • Kwon, Hyuck-Moo;Bai, Do-Sun
    • Journal of Korean Institute of Industrial Engineers
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    • v.22 no.1
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    • pp.17-36
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    • 1996
  • An economic two-stage screening procedure is presented when both lower and upper specification limits are given on the performance variable. A screening variable which is highly correlated with the performance variable is used first to decide whether an item should be accepted, rejected, or undecided. The performance variable is then used to classify the undecided items. The two variables are assumed to be jointly normally distributed. A cost model is constructed on the basis of six cost components; inspection costs of screening and performance variables and costs caused by type I and type II misclassification errors related with lower and upper specification limits. Optimal cutoff values on the screening variable are determined so that the average outgoing quality exceeds a prespecified level. Solution methods are provided for both known-parameter and unknown-parameter cases.

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