• Title/Summary/Keyword: the continuous method

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Early and Mid-Term Results of MIDCAB (최소 침습적 관상 동맥 우회술의 중단기 성적)

  • 손호성;방영호;황진욱;민병주;조양현;박성민;이성호;김광택;선경
    • Journal of Chest Surgery
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    • v.37 no.10
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    • pp.827-832
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    • 2004
  • Background: The significance of MIDCAB is emerging topics recently as OPCAB is going to be universalized, and long-term outcome of bypass graft surgery was proved to be more excellent than balloon dilation or stent insertion. We report our MIDCAB results in 73 patients in the last three years. Material and Method: Retrospective analysis of medical records was done from November 1, 2000 through November 31, 2003. There were 47 males and 26 females ranging in age from 31 years to 79 years (average $61.3\pm9.8$ years). Observation periods after operative procedures were 10 to 1238 days (average $763\pm319.8$ days). Left longitudinal parasternal incision as a standard procedure was done to approach the heart after dissection of the left internal thoracic artery by partial or total resection of 3rd to 5th ribs. Result: Of those patients, 46 patients were transferred to ICU after extubation at operation room and 58 patients were extubated within 3 hours after operation. Average ICU staying periods was $26.8\pm11.5$ hours. Follow-up angiography during admission was done in 36 patients and showed 100% patency. Only one patient died on the 10$^{th}$ post operative day because of sudden CVA. Complications included wound problems in 4 patients, and constructing pericardial window using thoracoscopy due to continuous pericardial effusion in 1. Permanent pacemaker was inserted in one patient owing to sick sinus syndrome. In one patient with recurrence of angina 8 months after operation, stenosis at anastomic site was found and improved with balloon dilatation. Conclusion: We were satisfied with our results of MIDCAB in single and multi-vessel coronary artery disease. These results have made the cardiologists tried to operate positively and we expect widening operative indications including hybrid revascularization.

Result of Tracheal Resection and End-to-end Anastomosis (기관 절제 및 단단문합술의 성적 고찰)

  • 유양기;박승일;박순익;김용희;박기성;김동관;최인철
    • Journal of Chest Surgery
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    • v.36 no.4
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    • pp.267-272
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    • 2003
  • Background: Common treatment modalities for tracheal stenosis include conservative methods such as repeated balloon dilatation, removal of obstructive material through bronchoscopy and T-tube insertion as well as operative treatment methods. Recent advances in surgical approaches through tracheal resection and end-to-end anastomosis have been reported to give better functional and anatomical results. Material and Method: Between March 1990 and July 2002, 41 patients who received tracheal resection and end-to-end anastomosis at Asan Medical Center, University of Ulsan were studied retrospectively. Result: The causes for tracheal resection and end-to-end anastomosis included 26 cases of postintubation stenosis, 10 cases of primary tracheal tumors (3 benign, 7 malignant), 1 case of endobronchial tuberculosis, 2 cases of traumatic rupture, and 2 cases of tracheal invasion of a thyroid cancer, Of the 41 patients who received tracheal resection and reconstruction, 29 received tracheal resection and end-to-end anastomosis, and 12 received laryngotracheal anastomosis with cricoid or thyroid cartilage resection. Four of these patients received supralaryngeal release. The average length of the resected trachea was $3.6{\pm}1.0$cm. Of the 41 patients who received tracheal resection and end-to-end anastomosis, 30 (73.2%) experienced no postoperative complications, and 8 (19.5%) experienced granulation tissue growth and/or minor infections which improved after conservative management. Good or satisfactory results were therefore achieved in 92.7%. Complications included repeated granulation tissue growth in 7, wound infection in 2, anastomotic site dehiscence in 2, restenosis resulting in dyspnea on exertion in 1, and repeated postoperative aspiration requiring retracheostomy in 1. There was no early postoperative mortality. There were 3 cases of hospital death. Conclusion: In cases of proper length of tracheal lesion, excellent results were obtained after tracheal resection and end-to-end anastomosis. But, granulation tissue growth is so serious complication, it is necessary for continuous study and efforts to prevent it.

Relationship Between Exercise Induced Asthma and Gastroesophageal Reflux (운동유발성 천식과 위식도역류와의 연관성)

  • Lee, Heung-Bum;Lee, Yang-Deok;Kim, Hyun-Chul;Lee, Yong-Chul;Lee, Soo-Teik;Rhee, Yang-Keun
    • Tuberculosis and Respiratory Diseases
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    • v.48 no.2
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    • pp.203-209
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    • 2000
  • Background: Exercise is a very common precipitant of asthma. Bronche-constriction associated with exercise can occur in 75~90% of individuals with asthma The estimated prevalence(30~85%) of gastroesophageal reflux(GER) in patients with asthma is significantly higher than in general population. We performed pH monitoring during the exercise in order to evaluate whether exercise induced asthma(EIA) could be related to GER and acid reflux-induced esophagobronchial reflex-mediated bronchospasm might be a factor for EIA. Method: Following an overnight fast, 18 patients with a suspected EIA(6 men, 12 women) were studied. Monitoring of intraesophageal pH, ECG and spirometry was done for 1 hour before treadmill exercise. After baseline monitoring, subjects underwent symptom-limited treadmill exercise with Bruce protocol and continuous monitoring for 60 min after exercise. Spirometry was done at baseline prior to exercise, and repeated every 10 min after full exercise for 60 min. Results: Exercise-induced bronchoconstriction was noted in 15 patients, who performed MBPT and 12 patients confirmed for bronchial asthma and 3 patients were diagnosed exercise-induced astham. Five of 15 EIA patients demonstrated a pathologic degree of GER. Conclusion: We suggest that GER may be one of pathophysiologic factors of EIA and evoke further concentration on the GER in the EIA patients.

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The Effect of Pressure Support on Respiratory Mechanics in CPAP and SIMV (CPAP 및 SIMV Mode하에서 Pressure Support 사용이 호흡역학에 미치는 효과)

  • Lim, Chae-Man;Jang, Jae-Won;Choi, Kang-Hyun;Lee, Sang-Do;Koh, Youn-Suck;Kim, Woo-Sung;Kim, Dong-Soon;Kim, Won-Dong;Park, Pyung-Whan;Choi, Jong-Moo
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.3
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    • pp.351-360
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    • 1995
  • Background: Pressure support(PS) is becomimg a widely accepted method of mechanical ventilation either for total unloading or for partial unloading of respiratory muscle. The aim of the study was to find out if PS exert different effects on respiratory mechanics in synchronized intermittent mandatory ventilation(SIMV) and continuous positive airway pressure (CPAP) modes. Methods: 5, 10 and 15 cm $H_2O$ of PS were sequentially applied in 14 patients($69{\pm}12$ yrs, M:F=9:5) and respiratory rate (RR), tidal volume($V_T$), work of breathing(WOB), pressure time product(PTP), $P_{0.1}$, and $T_1/T_{TOT}$ were measured using the CP-100 pulmonary monitor(Bicore, USA) in SIMV and CPAP modes respectively. Results: 1) Common effects of PS on respiratory mechanics in both CPAP and SIMV modes As the level of PS was increased(0, 5, 10, 15 cm $H_2O$), $V_T$ was increased in CPAP mode($0.28{\pm}0.09$, $0.29{\pm}0.09$, $0.31{\pm}0.11$, $0.34{\pm}0.12\;L$, respectively, p=0.001), and also in SIMV mode($0.31{\pm}0.15$, $0.32{\pm}0.09$, $0.34{\pm}0.16$, $0.36{\pm}0.15\;L$, respectively, p=0.0215). WOB was decreased in CPAP mode($1.40{\pm}1.02$, $1.01{\pm}0.80$, $0.80{\pm}0.85$, $0.68{\pm}0.76$ joule/L, respectively, p=0.0001), and in SIMV mode($0.97{\pm}0.77$, $0.76{\pm}0.64$, $0.57{\pm}0.55$, $0.49{\pm}0.49$ joule/L, respectively, p=0.0001). PTP was also decreased in CPAP mode($300{\pm}216$, $217{\pm}165$, $179{\pm}187$, $122{\pm}114cm$ $H_2O{\cdot}sec/min$, respectively, p=0.0001), and in SIMV mode($218{\pm}181$, $178{\pm}157$, $130{\pm}147$, $108{\pm}129cm$ $H_2O{\cdot}sec/min$, respectively, p=0.0017). 2) Different effects of PS on respiratory mechanics in CP AP and SIMV modes By application of PS (0, 5, 10, 15 cm $H_2O$), RR was not changed in CPAP mode($27.9{\pm}6.7$, $30.0{\pm}6.6$, $26.1{\pm}9.1$, $27.5{\pm}5.7/min$, respectively, p=0.505), but it was decreased in SIMV mode ($27.4{\pm}5.1$, $27.8{\pm}6.5$, $27.6{\pm}6.2$, $25.1{\pm}5.4/min$, respectively, p=0.0001). $P_{0.1}$ was reduced in CPAP mode($6.2{\pm}3.5$, $4.8{\pm}2.8$, $4.8{\pm}3.8$, $3.9{\pm}2.5\;cm$ $H_2O$, respectively, p=0.0061), but not in SIMV mode($4.3{\pm}2.1$, $4.0{\pm}1.8$, $3.5{\pm}1.6$, $3.5{\pm}1.9\;cm$ $H_2O$, respectively, p=0.054). $T_1/T_{TOT}$ was decreased in CPAP mode($0.40{\pm}0.05$, $0.39{\pm}0.04$, $0.37{\pm}0.04$, $0.35{\pm}0.04$, respectively, p=0.0004), but not in SIMV mode($0.40{\pm}0.08$, $0.35{\pm}0.07$, $0.38{\pm}0.10$, $0.37{\pm}0.10$, respectively, p=0.287). 3) Comparison of respiratory mechanics between CPAP+PS and SIMV alone at same tidal volume. The tidal volume in CPAP+PS 10 cm $H_2O$ was comparable to that of SIMV alone. Under this condition, the RR($26.1{\pm}9.1$, $27.4{\pm}5.1/min$, respectively, p=0.516), WOB($0.80{\pm}0.85$, 0.97+0.77 joule/L, respectively, p=0.485), $P_{0.1}$($3.9{\pm}2.5$, $4.3{\pm}2.1\;cm$ $H_2O$, respectively, p=0.481) were not different between the two methods, but PTP($179{\pm}187$, $218{\pm}181 cmH_2O{\cdot}sec/min$, respectively, p=0.042) and $T_1/T_{TOT}$($0.37{\pm}0.04$, $0.40{\pm}0.08$, respectively, p=0.026) were significantly lower in CPAP+PS than in SIMV alone. Conclusion: PS up to 15 cm $H_2O$ increased tidal volume, decreased work of breathing and pressure time product in both SIMV and CPAP modes. PS decreased respiration rate in SIMV mode but not in CPAP mode, while it reduced central respiratory drive($P_{0.1}$) and shortened duty cycle ($T_1/T_{TOT}$) in CPAP mode but not in SIMV mode. By 10 em $H_2O$ of PS in CPAP mode, same tidal volume was obtained as in SIMV mode, and both methods were comparable in respect to RR, WOB, $P_{0.1}$, but CPAP+PS was superior in respect to the efficiency of the respiratory muscle work (PTP) and duty cycle($T_1/T_{TOT}$).

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Comparison of 99mTc-Tin colloid colloid and 99mTc-DISIDA Hepatoscintigraphy in Miniature Pigs (미니돼지에서 99mTc-Tin colloid와 99mTc-DISIDA를 사용한 간신티그라피의 비교 연구)

  • Shim, Kyung-Mi;Kim, Se-Eun;Lee, Won-Guk;Koong, Sung-Soo;Bae, Chun-Sik;Lee, Jae-Yeong;Choi, Seok-Hwa;Han, Ho-Jae;Kang, Seong-Soo;Park, Soo-Hyun
    • Journal of Life Science
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    • v.16 no.6
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    • pp.1060-1065
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    • 2006
  • Non-invasive evaluation of liver function in animal models remains a challenge. Hepatoscintigraphy provides information about changes in liver size and shape, and enables to understand general liver function. Futhermore it is readily used to diagnosis complications of liver transplantation like hepatitis, rejections and biliary complications. In this study, we investigated the usefulness of evaluating the liver function in miniature pigs with $^{99m}Tc-Tin$ colloid and $^{99m}Tc-DISIDA$ which are the most commonly used radiopharmaceuticals in human medicine. In result, $^{99m}Tc-Tin$ colloid was uptaked in lung, liver, gastric wall and kidney in miniature pigs. And $^{99m}Tc-DISIDA$ showed continuous uptake images of heart, lung, liver, gallbladder and duodenum, and it was similar to human's. Therefore we could conclude $^{99m}Tc-Tin$ colloid would not be suitable for evaluating hepatic function because of it's nonspecific affinity, however $^{99m}Tc-DISIDA$ scintigraphy would be an effective method for detecting hepatobiliary function in miniature pigs.

Studies on the Appraisal of Stumpage Value in the Forest Land - With Respect to Kyung-Ju Area - (산원지(山元地) 임목평가(林木平価)에 관(関)한 연구(研究) - 경주지방(慶州地方)을 중심(中心)으로 -)

  • Rha, Sang Soo;Park, Tai Sik
    • Journal of Korean Society of Forest Science
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    • v.52 no.1
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    • pp.37-49
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    • 1981
  • The purpose of the study is to find out the objective method of valuation on the forest stands through the analysis of logging costs that is positively related to timber production. The two forest (Amgog, Whangryoung), located nereby, but forest type, logging and skidding conditions being slightly different, were slected to carry out the study. The objective timber stumpage value were determined by investigating the appropriate timber production costs and profits of logging operations. The main result obtained in this study are as follows: 1. The rate of logging cost in consisting of timber market price is 13.15% in the area of Amgog logging place and 19.48% in Whangryoung. 2. The rate of the other production cost excluding logging cost is 15.36% in the area of Amgog logging place and 28.85% in Whangryoung. 3. The total rate of timber production cost in consisting of the market price is more than 28.51% in the area of Amgog logging place and 48.33% in Whangryoung, 4. Though the productivity of forest land is affected by the selection of tree species, tending, treatments and effective management of forest land, the more important problem is improvement of logging condition. 5. The rate of production cost in timber price is so high that we should endeavore to improve the productivity of labour and its quality, and minimize the difference of piece work per day in accordance to the various site condition. 6. Although the profit of forest industry is related to the period of recapturing investment, it is more closely related to the working condition, risk of investment and continuous change of social investment interest. 7. If the right variables which are related to the timber market, are objectively obtained, the stumpage value of mature forests can be objectively caculated by applying straight line discounting method or compound discounting method in caculating the stump to market price.

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Analysis of Greenhouse Thermal Environment by Model Simulation (시뮬레이션 모형에 의한 온실의 열환경 분석)

  • 서원명;윤용철
    • Journal of Bio-Environment Control
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    • v.5 no.2
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    • pp.215-235
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    • 1996
  • The thermal analysis by mathematical model simulation makes it possible to reasonably predict heating and/or cooling requirements of certain greenhouses located under various geographical and climatic environment. It is another advantages of model simulation technique to be able to make it possible to select appropriate heating system, to set up energy utilization strategy, to schedule seasonal crop pattern, as well as to determine new greenhouse ranges. In this study, the control pattern for greenhouse microclimate is categorized as cooling and heating. Dynamic model was adopted to simulate heating requirements and/or energy conservation effectiveness such as energy saving by night-time thermal curtain, estimation of Heating Degree-Hours(HDH), long time prediction of greenhouse thermal behavior, etc. On the other hand, the cooling effects of ventilation, shading, and pad ||||&|||| fan system were partly analyzed by static model. By the experimental work with small size model greenhouse of 1.2m$\times$2.4m, it was found that cooling the greenhouse by spraying cold water directly on greenhouse cover surface or by recirculating cold water through heat exchangers would be effective in greenhouse summer cooling. The mathematical model developed for greenhouse model simulation is highly applicable because it can reflects various climatic factors like temperature, humidity, beam and diffuse solar radiation, wind velocity, etc. This model was closely verified by various weather data obtained through long period greenhouse experiment. Most of the materials relating with greenhouse heating or cooling components were obtained from model greenhouse simulated mathematically by using typical year(1987) data of Jinju Gyeongnam. But some of the materials relating with greenhouse cooling was obtained by performing model experiments which include analyzing cooling effect of water sprayed directly on greenhouse roof surface. The results are summarized as follows : 1. The heating requirements of model greenhouse were highly related with the minimum temperature set for given greenhouse. The setting temperature at night-time is much more influential on heating energy requirement than that at day-time. Therefore It is highly recommended that night- time setting temperature should be carefully determined and controlled. 2. The HDH data obtained by conventional method were estimated on the basis of considerably long term average weather temperature together with the standard base temperature(usually 18.3$^{\circ}C$). This kind of data can merely be used as a relative comparison criteria about heating load, but is not applicable in the calculation of greenhouse heating requirements because of the limited consideration of climatic factors and inappropriate base temperature. By comparing the HDM data with the results of simulation, it is found that the heating system design by HDH data will probably overshoot the actual heating requirement. 3. The energy saving effect of night-time thermal curtain as well as estimated heating requirement is found to be sensitively related with weather condition: Thermal curtain adopted for simulation showed high effectiveness in energy saving which amounts to more than 50% of annual heating requirement. 4. The ventilation performances doting warm seasons are mainly influenced by air exchange rate even though there are some variations depending on greenhouse structural difference, weather and cropping conditions. For air exchanges above 1 volume per minute, the reduction rate of temperature rise on both types of considered greenhouse becomes modest with the additional increase of ventilation capacity. Therefore the desirable ventilation capacity is assumed to be 1 air change per minute, which is the recommended ventilation rate in common greenhouse. 5. In glass covered greenhouse with full production, under clear weather of 50% RH, and continuous 1 air change per minute, the temperature drop in 50% shaded greenhouse and pad & fan systemed greenhouse is 2.6$^{\circ}C$ and.6.1$^{\circ}C$ respectively. The temperature in control greenhouse under continuous air change at this time was 36.6$^{\circ}C$ which was 5.3$^{\circ}C$ above ambient temperature. As a result the greenhouse temperature can be maintained 3$^{\circ}C$ below ambient temperature. But when RH is 80%, it was impossible to drop greenhouse temperature below ambient temperature because possible temperature reduction by pad ||||&|||| fan system at this time is not more than 2.4$^{\circ}C$. 6. During 3 months of hot summer season if the greenhouse is assumed to be cooled only when greenhouse temperature rise above 27$^{\circ}C$, the relationship between RH of ambient air and greenhouse temperature drop($\Delta$T) was formulated as follows : $\Delta$T= -0.077RH+7.7 7. Time dependent cooling effects performed by operation of each or combination of ventilation, 50% shading, pad & fan of 80% efficiency, were continuously predicted for one typical summer day long. When the greenhouse was cooled only by 1 air change per minute, greenhouse air temperature was 5$^{\circ}C$ above outdoor temperature. Either method alone can not drop greenhouse air temperature below outdoor temperature even under the fully cropped situations. But when both systems were operated together, greenhouse air temperature can be controlled to about 2.0-2.3$^{\circ}C$ below ambient temperature. 8. When the cool water of 6.5-8.5$^{\circ}C$ was sprayed on greenhouse roof surface with the water flow rate of 1.3 liter/min per unit greenhouse floor area, greenhouse air temperature could be dropped down to 16.5-18.$0^{\circ}C$, whlch is about 1$0^{\circ}C$ below the ambient temperature of 26.5-28.$0^{\circ}C$ at that time. The most important thing in cooling greenhouse air effectively with water spray may be obtaining plenty of cool water source like ground water itself or cold water produced by heat-pump. Future work is focused on not only analyzing the feasibility of heat pump operation but also finding the relationships between greenhouse air temperature(T$_{g}$ ), spraying water temperature(T$_{w}$ ), water flow rate(Q), and ambient temperature(T$_{o}$).

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A Study of the Health Service Computerization State and the Occupational Nurses's Satisfaction Level on Computerization (산업간호현장의 보건업무 전산화시스템 활용현황과 산업간호사의 전산화 직무만족도 연구)

  • Jung, Hee Young;Park, Hyoung-Sook
    • Korean Journal of Occupational Health Nursing
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    • v.13 no.1
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    • pp.5-18
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    • 2004
  • This study aims to investigate the use state of the health service computerization system in the occupational nursing field and the occupational nursers' satisfaction level, and provide basic data to promote the development of the health service computerization system for the nursing field. For this study, a questionnaire was provided to 118 occupational nurses who belong to Busan and Gyeongnam branches of KAOHN(Korean Association of Occupational Health Nurses) for 2 months (from Dec. 1, 2002 to Jan. 31, 2003). A tool of Choi Yong-Heui(2000) was used to investigate the satisfaction level of using the health service computerization system. The collected materials were analyzed in real number and percentage, average and standard deviation, t-test and ANOVA by using the SPSS WIN 10.0 program. This study is summarized as follows: 1. The average age was $31.99{\pm}5.58$ old in this study. The married were 54.2%. Participants who graduated from a junior college was 76.9%. The average service period was $4.48{\pm}4.68$ years. In service types, 79.7% of participants served in a health care center. The average service period was $3.22{\pm}2.89$ years. The service place which had 1000 workers or more was 35.6%. 2. Only 20.3% of participants in this study had a computer use education. 3. The field who participants used mostly was communication/internet, $3.29{\pm}.85$ hours in average. 4. 97.1% of occupational fields had computers and peripheral devices: 71.4% in pentium computer, 42.8% in the hard disk capacity of 20-29GB, 60.0% in 15 inch monitors, 86.2% in printers, 18.1% in digital cameras, 12.4% in LAN, and 9.5% in scanners. 80.1% of the occupational fields which were objects of study could use communication. 5. The occupational fields which did not introduced the health service computerization system were 62.8%. The main cause was attributable to entrepreneurs' insufficient recognition 66.6%. 51.5% of the entrepreneurs did not have an introduction plan. 37.2% of participating companies had the health service computerization system. 56.4% of them introduced it since the year 2000. 81.6% of the introduction motivation aimed to the efficiency of health service. The most issue upon introduction was insufficient understanding of a person in charge - 25.6%. The in-house development of the system covered 56.4%. 61.5% of the participants accepted their demands from the first stage of development. The direct effect of computerization showed the increase of 25.9% in the quickness and continuity of service treatment, and 25.9% in the serviceability of statistical treatment. 6. 22.0% of the participants had a computerization system use education. 69.2% of them had a in-house education. An educational method by nurses who used the computerization system was 76.9%. 92.3% of the education was helpful for practical duties. 7. An analysis of the computer use by health service fields showed that the medicine management in a health management field was 15.9%. the work environment measuring management in a work environment filed was 32.9%. the employment. general and special examination management in a heal th management field was 61.1 %. the various reports management in an administrative field was 64%. the health education data preparation management in an educational field was 58.0%. and the medicine and expendables management in an equipment management field was 51.6%. An analysis of the computerization system use showed that the various statistical data manage in a health management field was 13.0%. the work environment measuring management in a health management field was 34.8%. the personal disease management in a health management field was 51.9%. the heal education data preparation management in an educational field was 54.5%. and the equipment management of health care centers in an equipment management field was 52.6%. 8. 31.6% of the participants wanted that health service computerization system would include the generals of health services. 42.4% of the participants thought that first of all. the aggressive interest and investment of employers were required to build the health service computerization system. 9. The participants' satisfaction level on the computerization system use was $3.51{\pm}.57$ points. An analysis by each factor showed $3.62{\pm}.68$ points in a service change factor. $3.15{\pm}.63$ points in a computer program use factor, and $3.45{\pm}.71$ points in a continuous computerization use factor. 10. An analysis of the computerization system use by general characteristics of participants showed that the married (p = .022) had the satisfaction level higher than the unmarried. 11. The satisfaction level of the computerization system use by participants' computer use ability tended to be higher in proportion to the increase of computer use abilities in spreadsheet (F=2.606. p=.048). presentation (F=3.62. p=.012) and communication/internet(F=2.885. p=.0321. Based on the study results mentioned above. I will suggest as follows : The nationwide enlargement and repetition study is required for occupational nurses who serve in occupational nursing fields. The computerization system in a health service field is inferior comparing with other fields. The computerization system standard by business types and characteristics should be prepared through employers's aggressive participation and national support. Therefore various statistical data which occurs in occupational fields will be managed systematically and efficiently. A regular and systematic computer education plan for occupational nurses in charge of health services in the filed is urgently required to efficiently manage and improve the health of on-site workers.

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A study on the prediction of korean NPL market return (한국 NPL시장 수익률 예측에 관한 연구)

  • Lee, Hyeon Su;Jeong, Seung Hwan;Oh, Kyong Joo
    • Journal of Intelligence and Information Systems
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    • v.25 no.2
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    • pp.123-139
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    • 2019
  • The Korean NPL market was formed by the government and foreign capital shortly after the 1997 IMF crisis. However, this market is short-lived, as the bad debt has started to increase after the global financial crisis in 2009 due to the real economic recession. NPL has become a major investment in the market in recent years when the domestic capital market's investment capital began to enter the NPL market in earnest. Although the domestic NPL market has received considerable attention due to the overheating of the NPL market in recent years, research on the NPL market has been abrupt since the history of capital market investment in the domestic NPL market is short. In addition, decision-making through more scientific and systematic analysis is required due to the decline in profitability and the price fluctuation due to the fluctuation of the real estate business. In this study, we propose a prediction model that can determine the achievement of the benchmark yield by using the NPL market related data in accordance with the market demand. In order to build the model, we used Korean NPL data from December 2013 to December 2017 for about 4 years. The total number of things data was 2291. As independent variables, only the variables related to the dependent variable were selected for the 11 variables that indicate the characteristics of the real estate. In order to select the variables, one to one t-test and logistic regression stepwise and decision tree were performed. Seven independent variables (purchase year, SPC (Special Purpose Company), municipality, appraisal value, purchase cost, OPB (Outstanding Principle Balance), HP (Holding Period)). The dependent variable is a bivariate variable that indicates whether the benchmark rate is reached. This is because the accuracy of the model predicting the binomial variables is higher than the model predicting the continuous variables, and the accuracy of these models is directly related to the effectiveness of the model. In addition, in the case of a special purpose company, whether or not to purchase the property is the main concern. Therefore, whether or not to achieve a certain level of return is enough to make a decision. For the dependent variable, we constructed and compared the predictive model by calculating the dependent variable by adjusting the numerical value to ascertain whether 12%, which is the standard rate of return used in the industry, is a meaningful reference value. As a result, it was found that the hit ratio average of the predictive model constructed using the dependent variable calculated by the 12% standard rate of return was the best at 64.60%. In order to propose an optimal prediction model based on the determined dependent variables and 7 independent variables, we construct a prediction model by applying the five methodologies of discriminant analysis, logistic regression analysis, decision tree, artificial neural network, and genetic algorithm linear model we tried to compare them. To do this, 10 sets of training data and testing data were extracted using 10 fold validation method. After building the model using this data, the hit ratio of each set was averaged and the performance was compared. As a result, the hit ratio average of prediction models constructed by using discriminant analysis, logistic regression model, decision tree, artificial neural network, and genetic algorithm linear model were 64.40%, 65.12%, 63.54%, 67.40%, and 60.51%, respectively. It was confirmed that the model using the artificial neural network is the best. Through this study, it is proved that it is effective to utilize 7 independent variables and artificial neural network prediction model in the future NPL market. The proposed model predicts that the 12% return of new things will be achieved beforehand, which will help the special purpose companies make investment decisions. Furthermore, we anticipate that the NPL market will be liquidated as the transaction proceeds at an appropriate price.

The Environmental and Ecological Meaning of Bibo Landscape in Otgol Village (옻골마을 비보경관의 환경생태적 의미)

  • Jang, Byoung-Kwan;Whang, Bo-Chul
    • Journal of the Korean Institute of Landscape Architecture
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    • v.36 no.2
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    • pp.32-41
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    • 2008
  • An empirical study and environmental and ecological analysis were conducted on Otgol Village(a village of the Gyeongju Choi's clan in Daegu) where an enclosed pond and groves are still observed. In particular, the enclosed pond and groves and village water system were investigated from an ecological perspective. The enclosed landscape is described based on feng shui principles and the environmental and ecological significance were examined. In general, the environmental and ecological significance is very broad; however, they were analyzed in terms of the quality of life as an empirical study as follows: First, water quality was measured to investigate the improvement of continuous water system functions. In other words, water quality was measured at East Valley(resting space), West Valley(living space), the enclosed pond where the two valleys merge, and the stream that flows out of the pond. Second, the climate functions of the enclosed groves that border the village were examined. In other words, temperature was measured in two places(200m distance from the center of the groves). Third, whether or not a sound ecosystem can be sustained was investigated. In other words, landscape ecological indicators were chosen and measured. The results are as follows: First, the enclosed pond played the role of purifying water quality. While the East Valley has been popular with men for its rock walls and torrents, the West Valley has been popular with women as a living space(ex: doing the laundry). Therefore, the difference of water quality can be explained. Second, since enclosed groves are in a small village forest, they are very weak in terms of being wind proof and temperature reduction effects. Instead, they play the role of the village boundary. Third, the groves are ecologically sound considering the landscape ecological indicators and are similar to ordinary traditional rural villages. In terms of the connection of the green zone, the village groves are well connected to the village boundary wood. If the village groves are restored, in particular, they would offer a decent habitat for grove creatures. According to this study, the traditional village space was formed upon the influence of Feng Shui theories that are based on environmental and ecological principles that focus on the harmony between humans and nature. From the environmental and ecological perspective, the enclosed pond and groves are important factors in building a sustainable village. The diverse water space would help to improve water quality and increase water volume by promoting the water circulation system. In addition, the village woods would surround the village and decrease the temperature and humidity difference between winter and summer. If the groves are small and badly damaged, however, they are meaningful only in dividing the region. The overall improvement of a forestation system and botanical composition may increase the biological diversity and promote the migration of species. Otgol Village has developed an enclosed landscape to improve the village environment. In other words, a sound and refreshing living environment can be developed when the natural ecological system is well understood and properly preserved. Additionally, this traditional village planning will be the environmental and ecological method. From the perspective of environmental ecology, therefore, a traditional village is recommended.