• 대한조선학회논문집
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• 제40권5호
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• pp.60-67
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• 2003

For risk or reliability assessment of ship structures against particular hazardous situations such as total loss or sinking due to hull girder collapse, the short-term based response analysis rather than the long-term response analysis is required to determine wave-induced bending moments when the ship encounters a storm of specific duration and with a specified small encounter probability. In the present study, the effects of operational condition and sea states on wave-induced bending moments of large merchant vessels are investigated. A series of the short-term response analyses for a hypothetical VLCC and a Capesize bulk carrier (CSBC) are carried out with varying operational condition and sea states which include ship speed, significant wave height and wave persistence time, using the linear-strip theory based program ABS/SHIPMOTION and the MIT sea-keeping tables. The computed results are also compared with the IACS design formula predictions. The results and insights developed from the present study are summarized.

• 동력기계공학회지
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• 제13권2호
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• pp.63-70
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• 2009

This paper discusses the influence on long-tenn predictions of the ship response in ocean by using the Global Wave Statistics data, GWS, and wave information from the remote sensing satellites. GWS's standard scatter diagrams of significant wave height and zero-crossing wave period are suggested to be corrected to a round number of 0.01/1000 fitted with a statistical analytic model of the conditional lognormal distribution for zero-crossing wave period. The GEOSAT satellite data are utilized which presented by I. R. Young and G. J. Holland (1996, named as GEOSAT data). At first, qualities of this data are investigated, and statistical characteristic trends are studied by means of applying known probability distribution functions. The wave height data of GEOSAT are compared to the data observed onboard merchant ships, the data observed by measure instrument installed on the ocean-going container ship and so on. To execute a long-tenn prediction of ship response, joint probability functions between wave height and wave period are introduced, therefore long-term statistical predictions are executed by using the functions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.398-403
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• 1993

A rule based fuzzy expert system to self-tune PID controllers is proposed in this paper. The proposed expert system contains two rule bases, where one is responsible for "Long term tuning" and the other for "Incremental tuning". The rule for "Long term tuning" are extracted from the Wills'map and the knowledge about the implicit relations between PID gains and important long term features of the output response such as overshoot, damping and rise time, etc., while 'Incremental tuning" rules are obtained from the relations between PID gains and short term features, error and change in error. In the PID control environment, the proposed expert system operates in two phases sequentially. In the first phase, the long term tuning is performed until long term features meet their desired values approximately. Then the incremental tuning tarts with PID gains provided by the long term tuning procedure. It is noticeable that the final PID gains obtained in the incremental tuning phase are only the temporal ones. Simulation results show that the proposed rule base for "Long term tuning" provides superior control performance to that of Litt and that further improvement of control performance is obtained by the "Incremental tuning'.ance is obtained by the "Incremental tuning'.ing'.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.579-582
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• 1999

This paper represents the results of experiments designed to investigate the time-dependent response of concrete and steel tube in circular concrete-filled steel tubes, as are deployed extensively in high-rise building construction. The experiments were performed for creep of concrete and CFT column specimens with three loading cases. The creep coefficient and specific creep(unit creep) obtained from the test results were used for estimating and comparing the time-dependent response of each case. From these analyses, it is show that CFT-column has many merits for long-term behavior.

• 한국해양공학회지
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• 제30권6호
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• pp.440-450
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• 2016

The capsizing and consequent sinking of a coastal car ferry was recently reported, with numerous human casualties. The primary cause was determined to be a sudden turn with improperly stowed and secured cargo. Part I of this study introduces how long term acceleration components are determined from seakeeping analyses. A carferry with a displacement of 1,633 tonf was selected as the target vessel. Sea data that included the significant wave heights and periods were collected at four observation buoys, some of which were far away from two main voyage routes: Incheon-Jeju and Pusan-Jeju. Frequency response analyses were performed to obtain the linearized radiation force coefficients, hydrostatic stiffnesses, and wave excitation forces. Time response analyses were sequentially performed to produce the motion-induced acceleration processes. The probabilistic distributions of the acceleration components were determined using a peak and valley counting method. Long term extreme acceleration components were proposed as a final result.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제17권1호
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• pp.31-36
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• 2014

Purpose: Infliximab (IFX) is considered safe and effective for the treatment of ulcerative colitis (UC) in both adults and children. The aim of this study was to evaluate the short- and long-term clinical course of IFX in Korean children with UC. Methods: Pediatric patients with UC who had received IFX infusions between November 2007 and May 2013 at Samsung Medical Center were retrospectively investigated. The clinical efficacy of IFX treatment was evaluated at 8 weeks (short term) and 54 weeks (long term) after the initiation of IFX treatment using the Pediatric Ulcerative Colitis Activity Index (PUCAI). The degree of response to IFX treatment was defined as complete response (PUCAI score=0), partial response (decrement of PUCAI score${\geq}20$ points), and non-response (decrement of PUCAI score <20 points). Adverse events associated with IFX treatment were also investigated. Results: Eleven pediatric patients with moderate to severe UC had received IFX. The remission rate after IFX treatment was 46% (5/11) and 82% (9/11) at 8 weeks and 54 weeks after IFX treatment, respectively. All patients who were steroid-dependent before treatment with IFX achieved remission at 54 weeks and were able to stop treatment with corticosteroids, while all steroid-refractory patients failed to achieve remission at 54 weeks after treatment with IFX. Conclusion: Response to IFX treatment after 8 weeks may predict a favorable long-term response to IFX treatment in Korean pediatric UC patients.

• 보건행정학회지
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• 제4권2호
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• pp.27-57
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• 1994

The objective of running a long-term care institution is to provide services helpful for maintaining, supporting, and improving elderlies' optimum level of physical, mental, and psychosocial functioning. For the purpose of analyzing the current situations of institutional long term care facilities in Korea, 27 facilities were selected proportionately from each of the cities and provinces, out of the total 152 facilities. About 20% of those who were institutionalized during 25 August through 2 Qctober 1993, the 391 elderlies were chosen on a systematic random basis. The instrument of this study was developed by modifying the tools of CARE, MAI and PCTC. A multivariate approach of discriminant analysis and clustering technique were employed for this study. The Stiudy reveals that there is no clear differentiation of goals and functions among the longterm care institutions in Korea. Staffing patte군 of long-term care facilities shows a shortage of nurses, physical therapists, and dieticians. The linkage between acute care facilities and long-term care is weak, and administration of long-term care faciltiy is carried out by non-professionals. They are responsible for assessing health status before entering the facility, and evaluating elderlies' care. Therefore, it is not surprising to find that most of the facilities have accommodated agede regardless of their real needs and health status. Based upon findings of the analysis, this study has classified long-term care facilities into four types : Type I is to help elderlies maintain independence in daily living activities. Type II facilities have the objective of maintaining and improving the current level of elderlies' function. Type III is to maintain maximum independence of elderlies in activities of daily living. And Type IV is identified for the group of facilities designed to restore or improve functional abilities of elderlies. In conclusion, the following suggestions are made : the need for long-term care should be assessed by multidimensional measurement. Institutional long-term care facilities should be classified and developed in response to type of type of care and service need. Both acute and long-term care facilities should be linked together in order to support the evaluation of service operation and program development.

• 생물정신의학
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• 제9권1호
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• pp.34-41
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• 2002

Background:Since serotonin neurotrasnmission plays an important role in the pathophysiology of depression, the drug that acts on serotonin transporter can be an effective antidepressant. The aim of this study was to investigate the relationship between serotonin transporter polymorphisms(5-HTTLPR) and the long-term effect of the antidepressant treatment. Method:The 175 depressive patients, who met DSM-IV criteria for major depressive disorder or dysthymic disorder were enrolled into three year study. The genotypes of the patients were investigated by polymerase chain reaction of genomic DNA with promoter regions of the serotonin transporter gene. The patients were assessed by the Clinical Global Impression Scale, at the 1st visit, 8th week, 16th week, 1st year, 2nd and 3rd year after the antidepressant treatment. Result:The genotypes of 138 patients were investigated and 128 of them finished this 1st year study and 107 remained in the study after 2-year treatment, and, 97 completed this 3-year study. The therapeutic response of each subset was not different at 8th, 16th week, but the subset with homozygote(l/l) of long variant showed a better antidepressant therapeutic response than heterozygote(l/s). The heterozygote(l/s) showed a better response than the subset with homozygote(s/s) of short variant at 1st, 2nd and 3rd year after the antidepressant treatment in CGI-global improvement score. Conclusion:This result shows that the serotonin transporter polymorphism may be related to the long-term effect of antidepressant treatment and there may be also ethnic difference.

• 보건의료산업학회지
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• 제10권1호
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• pp.93-104
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• 2016

Objectives : The purpose of this study was to identify the determinants of the long-term influence of violence on hospital nurses. Methods : Three-hundred hospital nurses were recruited in B city, South Korea. They were asked to complete a questionnaire, and 282 data- sets were included in the multiple regression analysis. Results : Subjects experienced more episodes of verbal violence than that of physical threats or physical violence. Assailants tended to be patients and their caretakers rather than internal customers. Nurses who had religion, worked in a surgical ward, and a 3-6 year career perceived a high level of violent experiences compared to their counterparts. The determinants of the long-term influence of violence were physical violence (t=-2.705, p=.007), emotion-focused coping (t=3.049, p=.003), and emotional response (t=3.611, p<.001). The model was statistically significant explaining 13.0% of the variance (F=14.981, p<.001). Conclusions : Nurse managers should help nurses who are victims of hospital violence by teaching them not to depend on emotion-focused coping and by alleviating their emotional response to violence.

• Smart Structures and Systems
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• 제31권1호
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• pp.45-56
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• 2023

Vibration-based structural health monitoring is used to ensure the safety of structures by installing sensors in structures. The peak picking method, one of the applications of vibration-based structural health monitoring, is a method that analyze the dynamic characteristics of a structure using the peaks of the frequency response function. However, the results may vary depending on the person predicting the peak point; further, the method does not predict the exact peak point in the presence of noise. To overcome the limitations of the existing peak picking methods, this study proposes a new method to automate the modal analysis process by utilizing long short-term memory, a type of recurrent neural network. The method proposed in this study uses the time series data of the frequency response function directly as the input of the LSTM network. In addition, the proposed method improved the accuracy by using the phase as well as amplitude information of the frequency response function. Simulation experiments and lab-scale model experiments are performed to verify the performance of the LSTM network developed in this study. The result reported a modal assurance criterion of 0.8107, and it is expected that the dynamic characteristics of a civil structure can be predicted with high accuracy using data without experts.