• Title/Summary/Keyword: Single subject research

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Explicit Formulae for Characteristics of Finite-Capacity M/D/1 Queues

  • Seo, Dong-Won
    • ETRI Journal
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    • v.36 no.4
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    • pp.609-616
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    • 2014
  • Even though many computational methods (recursive formulae) for blocking probabilities in finite-capacity M/D/1 queues have already been produced, these are forms of transforms or are limited to single-node queues. Using a distinctly different approach from the usual queueing theory, this study introduces explicit (transform-free) formulae for a blocking probability, a stationary probability, and mean sojourn time under either production or communication blocking policy. Additionally, the smallest buffer capacity subject to a given blocking probability can be determined numerically from these formulae. With proper selection of the overall offered load ${\rho}$, the approach described herein can be applicable to more general queues from a computational point of view if the explicit expressions of random vector $D_n$ are available.

Development and Evaluation of Fall Impact Protective Clothing for the Elderly Women (여성 노인을 위한 낙상충격 보호팬츠 개발 및 평가)

  • Park, Jung Hyun;Lee, Jin Suk;Lee, Jeong Ran
    • Fashion & Textile Research Journal
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    • v.20 no.5
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    • pp.569-582
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    • 2018
  • The purpose of this study is to verify the impact protection performance and to evaluate the activity, design, fit, and pad characteristics of the fall impact protection clothing for elderly women. The protective clothing was designed as pants type and underwear type, and an impact protection pad in the form of a tightly connected regular hexagon piece was inserted in the hip and hip joints. The pad was made of two kinds of foam single pad and foam and gel combination pad so that they could be inserted into pants type and underwear type, respectively. The results of the shock absorption performance of the fall impact protective clothing showed that when the impact force of 4601N was applied to the pants type protective clothing, the impact force was reduced by 29% in the foam pad type and 26% in the gel and foam pad type. When the force of 5113N was applied to the underwear type, it decreased by 40% in the foam pad type and by 34% in the gel and foam pad type. As a result of wearing evaluation of subject group, it was found that fit and activity of underwear type was better than that of pants type. Foam pad type was evaluated to be lighter than gel and foam pad type in both the subject and the expert group and the gel and foam pad was evaluated to be more flexible in the expert group.

A study on the supply status of chemical substance information including MSDS and a way of improving Database management in Korea (국내 MSDS 등 화학물질정보의 제공실태와 DB관리 개선방안 연구)

  • Lee, Kwon Seob;Yoon, Seok Joon;Choi, Jae Wook;Kim, Hyun Ock;Lee, Jong Han;Yang, Jeong Sun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.17 no.1
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    • pp.63-70
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    • 2007
  • This study investigated the current management staus of chemical substance information on Material Safety Data Sheets(MSDS) and Chemical Information Cards(CIC) provided by Korea Occupational Safety & Health Agency(KOSHA) and also researched the kind and the characteristics of chemical substance information provided in other organizations. MSDS DB in Korean provided on KOSHANET(which is Kosha website) is 50,802 in total, among whom are single chemical substances with 31,870 kinds(18,932%) and are mixed chemical substances with 31,870 kinds(62.7%). The number of visiting MSDS DB on KOSHANET for the search of chemicals was 2,049,806. The number has increased each year. The CIC provided for workplaces is all 542 kinds : 14 harmful substances subject to permission, 168 harmful substances subject to management, 360 KOEL(Korean Occupational Exposure Limits) establishment substances. MSDS internationally provided by organizations producing MSDS DB was written with 16 sections, which is suitable for the writing basis of American Standards Institute(ANSI) and International Organization for Standardization(ISO) and provided chemical substance information on more than 100,000 kinds in most organizations.

A Research on Relationships between Stress Level of Parents in Single Parent Families and Life Satisfaction in accordance with Stress Removing Methods - Centering on Small Towns in Midsection Sphere - (스트레스해소법에 따른 한부모가정 부모의 스트레스와 생활만족도와의 관계 연구 - 중부권 소도시를 중심으로 -)

  • Oh, Seung-ha;Cho, Sung-Je
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.7 no.1
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    • pp.26-35
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    • 2014
  • This research aims to identify relationships between stress level of parents in single parent families and life satisfaction in accordance with methods of getting rid of stress. Subject of the research were 260 parents in single parent families, centering on small towns in midsection sphere based on answers to questionnaire executed from March 1, 2013 to July 31, 2013. Collected data were analyzed by executing frequency analysis, factor analysis, t-test, one-way ANOVA, correlation analysis, regression analysis, etc. and an empirical verification was performed at 5% of significance level. From the result of the research, stress level appeared according to factors in a sequence of economic power, physical strength, social relation, family, mentality, etc. and significant influence to life satisfaction was found depending on factors such as stress removing methods and controlling effect. And minor factors were shown in a sequence of finance, emotion and acknowledgement. Suggestive points of the research are thought to be significance of stress removing method to the enhancement of life satisfaction, which will be a good material for the establishment of fundamental supporting plans and development of programs for single parent families.

Analysis of Academic Research Trends Pertaining to Globalization of Korean Food (한식의 세계화 관련 학술적 연구 동향 분석)

  • Min, Kye-Hong
    • Korean journal of food and cookery science
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    • v.25 no.5
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    • pp.606-618
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    • 2009
  • The purpose of this study was to analyze research trends in scholarly journals that were related to the globalization of Korean food and to provide information on the future of these trends such as various creative subject selection and research methods. 70 papers pertaining to Korean food research, such as academic journals expected to be registered, and national-scale academic papers, were selected. This research was conducted from April 6 to April 22. 2009. The results of this study were as the follows: First, most of the papers, 20(28.6%), were published in the journal of Korean journal of food culture. In addition, most articles had a single author, 24(34.3%). In regard to the profession of the auther, university professor was the most frequent profession, 127 persons(68.3%). In terms of the research subjects, preference was the most dominant preference(19.2%). Investigatory research was the most frequent research method, 58 papers(82.9%). Furthermore, foreigners and natives were the most dominant research objects, 21 papers(30.0%). As for the analysis methods, frequency analysis, one-way ANOVA, T-test, reliability analysis, and factor analysis were used the most in that order. Future studies should includ papers for master's degrees and doctorial degrees.

Exploratory study on developing a support policy for adolescent parents: focusing on single mothers who become pregnant for the first time as teenage years (청소년부모의 지원정책 개발을 위한 조사연구 -10대에 첫 자녀를 임신한 미혼한부모를 대상으로-)

  • Lee, young ho;Park, ji yoon
    • Journal of Family Resource Management and Policy Review
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    • v.25 no.1
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    • pp.113-132
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    • 2021
  • Despite the diverse system development and improvement initiatives that have been created to improve the environments of child birth and nurturing, the birth rate in Korean society remains low. Some minor teenage single parents give birth and raise children. Teenage single parents are supported by the Single-Parent Family Support Act, but some of their needs are still not being addressed. As each single parent has different backgrounds and socioeconomic characteristics, an investigation is required for developing differentiated support in which they will be considered both parents and children. Therefore, this study identifies the unique problems encountered by teenage parents, focuses on single mothers giving birth, and explores measures that teenage parents can use to be independent members of civil society. Three suggestions are presented for the period from pregnancy and childbearing to parenting. First, there should be an education support plan that will enable them to finish tertiary education, and parent education. Second, measures should be created to initiate a change in direction in indifferent biological(real) fathers: these should enlighten and help them participate in rearing their children. Third, in addition to improvements of the current systems only targeting single parent-family support, which will help differentiate teenage parent support from adolescent single parent-family support, assistance should be given for teenage single parents to grow as a Subject of Rights through tailored independent support programs.

The Effects of Trunk Stabilization Training on a Stroke Patient's Postural Control and Activities of Daily Living: A Sing Subject Design (뇌졸중 환자의 체간안정화 훈련이 자세조절과 일상생활동작에 미치는 영향: 단일사례연구)

  • Nam, Ju-Hyeon;Shim, Gyeong-Bo;Gwak, Seong-Won
    • The Journal of Korean society of community based occupational therapy
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    • v.4 no.1
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    • pp.75-84
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    • 2014
  • Objective : This study intends to suggest an effective clinical intervention method for stroke patients by applying a trunk stabilization training program to a single stroke patient and investigating and analyzing the effects of the program on postural control and activities of daily living. Methods : The subject of this study was a 75 year-old female stroke patient hospitalized in C Hospital located in Gyeongju, Gyeongsangbuk-do. As for the research design, A-B-A reversal design was used with a single subject design; and the research period was a total of five weeks from April 21, 2014 to May 23, 2014. As for the research process, a total of 15 sessions were carried out including three sessions of baseline(A), nine sessions of an intervention period(B), and three sessions of maintenance(A'); and the trunk stabilization program was applied during the intervention period. To evaluate the participant's postural control and activities of living life, the Postural Assessment Scale for Stroke(PASS) and the modified Barthel Index(MBI) were used. Visual analysis was used in which collected data were plotted on a graph, using Microsoft Office Excel 2013. Results : In the postural control test, the mean scores improved from 11.7 in the baseline phase to 14.8 in the intervention phase and 15.3 in the maintenance phase. In the evaluation of activities of daily living, the score improved from 66(medium dependence) during the baseline period to 80(low dependence) after intervention and at the maintenance phase. Conclusion : It was found that the trunk stabilization training program showed effects on the stroke patient's postural control or alignment, and furthermore a beneficial improvement in the patient's performing the activities of daily living, as well.

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Analysis of Research Trends Related to Forest Play: Focusing on Domestic Dissertations (숲놀이 관련 연구 동향 분석: 국내 학위 논문 중심으로)

  • Kim, Minjung
    • Journal of Christian Education in Korea
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    • v.69
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    • pp.77-104
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    • 2022
  • The purpose of this study was to investigate the research trend of forest play. The purpose of this study is to provide basic data for the vitalization of forest play research by analyzing the research period, research content, and research methods. For this study, 57 domestic master's and doctoral dissertations were extracted through the National Assembly Library and the Research Information Sharing Service(RISS) with the keywords of 'forest', 'play', and 'forest play'. The frequency and percentage were calculated by analyzing forest play research based on four criteria: research period, research content, research method, and research subject. As a result of the research, first, the trend of forest play research by period is from 2011 to 2021, with 49 articles (85.9%) for master's degrees and 8 articles (14.1%) for doctor's degrees. Second, the trend by research content was found to be 16 basic studies (28.1%) and 41 practical studies (71.9%). Forest play research is being actively conducted centered on practical research. Third, the trends by research method were in the order of 39 quantitative studies (68.4%), 17 qualitative studies (29.8%), and 1 literature study (1.8%). Forest play research is focused on quantitative research, and comparatively qualitative research and literature research account for a low proportion. Fourth, the trend by study subject was 56 single subject studies (98.2%). The single subjects were 52 children (91.2%), 3 teachers (5.2%), and 1 parent (1.8%). As for the mixed subjects, there is one study (1.8%) targeting children and parents, and it is necessary to conduct a study with mixed subjects. As for the study of material subjects, 42 articles (73.7%) in the natural environment, 13 articles (22.8%) in educational institutions, and 2 articles (3.5%) in the media were found in the order. Research on the home environment related to forest play is insufficient, so research on parents, children-parents, and home environment related to forest play should be conducted in the future.

Numerical Study on Aerodynamic Performance of Counter-rotating Propeller in Hover Using Actuator Method (Actuator 기법을 이용한 제자리 비행하는 동축 반전 프로펠러 공력 성능에 관한 수치적 연구)

  • Kim, Dahye;Park, Youngmin;Oh, Sejong;Park, Donghun
    • Journal of Aerospace System Engineering
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    • v.15 no.3
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    • pp.30-44
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    • 2021
  • Experimental investigation of counter-rotating propellers is subject to multiple time and cost constraint because of additional design parameters unlike single propeller. Also, a lot of computing time and resources are required for numerical analysis due to consideration of the interference between the upper and lower propellers. In the present study, numerical simulations were conducted to investigate the hover performance of counter-rotating propellers by using actuator method which is considered to be time-efficient. The accuracy of the present numerical methods was validated by comparing the ANSYS Fluent which is commercial CFD code. The axial spacing and rotational speed were selected as the analysis variables, and the aerodynamic performance was obtained under various conditions. Based on the obtained results, the Figure of Merit (FM) of single propeller and counter-rotating propellers and a prediction factor which enables prediction of counter-rotating propeller performance using a single propeller were derived to evaluate availability of the actuator method.

Feasibility Study of EEG-based Real-time Brain Activation Monitoring System (뇌파 기반 실시간 뇌활동 모니터링 시스템의 타당성 조사)

  • Chae, Hui-Je;Im, Chang-Hwan;Lee, Seung-Hwan
    • Journal of Biomedical Engineering Research
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    • v.28 no.2
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    • pp.258-264
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    • 2007
  • Spatiotemporal changes of brain rhythmic activity at a certain frequency have been usually monitored in real time using scalp potential maps of multi-channel electroencephalography(EEG) or magnetic field maps of magnetoencephalography(MEG). In the present study, we investigate if it is possible to implement a real-time brain activity monitoring system which can monitor spatiotemporal changes of cortical rhythmic activity on a subject's cortical surface, neither on a sensor plane nor on a standard brain model, with a high temporal resolution. In the suggested system, a frequency domain inverse operator is preliminarily constructed, considering the individual subject's anatomical information, noise level, and sensor configurations. Spectral current power at each cortical vertex is then calculated for the Fourier transforms of successive sections of continuous data, when a single frequency or particular frequency band is given. An offline study which perfectly simulated the suggested system demonstrates that cortical rhythmic source changes can be monitored at the cortical level with a maximal delay time of about 200 ms, when 18 channel EEG data are analyzed under Pentium4 3.4GHz environment. Two sets of artifact-free, eye closed, resting EEG data acquired from a dementia patient and a normal male subject were used to show the feasibility of the suggested system. Factors influencing the computational delay are investigated and possible applications of the system are discussed as well.