• 제목/요약/키워드: Statistical test

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Bankruptcy prediction using an improved bagging ensemble (개선된 배깅 앙상블을 활용한 기업부도예측)

  • Min, Sung-Hwan
    • Journal of Intelligence and Information Systems
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    • v.20 no.4
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    • pp.121-139
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    • 2014
  • Predicting corporate failure has been an important topic in accounting and finance. The costs associated with bankruptcy are high, so the accuracy of bankruptcy prediction is greatly important for financial institutions. Lots of researchers have dealt with the topic associated with bankruptcy prediction in the past three decades. The current research attempts to use ensemble models for improving the performance of bankruptcy prediction. Ensemble classification is to combine individually trained classifiers in order to gain more accurate prediction than individual models. Ensemble techniques are shown to be very useful for improving the generalization ability of the classifier. Bagging is the most commonly used methods for constructing ensemble classifiers. In bagging, the different training data subsets are randomly drawn with replacement from the original training dataset. Base classifiers are trained on the different bootstrap samples. Instance selection is to select critical instances while deleting and removing irrelevant and harmful instances from the original set. Instance selection and bagging are quite well known in data mining. However, few studies have dealt with the integration of instance selection and bagging. This study proposes an improved bagging ensemble based on instance selection using genetic algorithms (GA) for improving the performance of SVM. GA is an efficient optimization procedure based on the theory of natural selection and evolution. GA uses the idea of survival of the fittest by progressively accepting better solutions to the problems. GA searches by maintaining a population of solutions from which better solutions are created rather than making incremental changes to a single solution to the problem. The initial solution population is generated randomly and evolves into the next generation by genetic operators such as selection, crossover and mutation. The solutions coded by strings are evaluated by the fitness function. The proposed model consists of two phases: GA based Instance Selection and Instance based Bagging. In the first phase, GA is used to select optimal instance subset that is used as input data of bagging model. In this study, the chromosome is encoded as a form of binary string for the instance subset. In this phase, the population size was set to 100 while maximum number of generations was set to 150. We set the crossover rate and mutation rate to 0.7 and 0.1 respectively. We used the prediction accuracy of model as the fitness function of GA. SVM model is trained on training data set using the selected instance subset. The prediction accuracy of SVM model over test data set is used as fitness value in order to avoid overfitting. In the second phase, we used the optimal instance subset selected in the first phase as input data of bagging model. We used SVM model as base classifier for bagging ensemble. The majority voting scheme was used as a combining method in this study. This study applies the proposed model to the bankruptcy prediction problem using a real data set from Korean companies. The research data used in this study contains 1832 externally non-audited firms which filed for bankruptcy (916 cases) and non-bankruptcy (916 cases). Financial ratios categorized as stability, profitability, growth, activity and cash flow were investigated through literature review and basic statistical methods and we selected 8 financial ratios as the final input variables. We separated the whole data into three subsets as training, test and validation data set. In this study, we compared the proposed model with several comparative models including the simple individual SVM model, the simple bagging model and the instance selection based SVM model. The McNemar tests were used to examine whether the proposed model significantly outperforms the other models. The experimental results show that the proposed model outperforms the other models.

The Effect of Polypropylene Mulching Method on Growth of Quercus glauca Thunb. Seedling and Weed Treatments (부직포 멀칭 방식에 따른 종가시나무 묘목의 생장과 제초에 미치는 영향)

  • Sung, Chang-Hyun;Yoon, Jun-Hyuck;Jin, Eon-Ju;Bae, Eun-Ji
    • Journal of the Korean Institute of Landscape Architecture
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    • v.48 no.5
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    • pp.59-66
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    • 2020
  • Recently, cultivation and management technologies have been needed to adapt due to climate change, which is causing abnormal weather conditions. One technique is to increase the utilization of evergreen broad-leaved species with high ornamental value. A total of five treatments were installed (1m×22.5m), including 60g/㎡ and 80g/㎡ using two types mulching material with an overlapping and hole-drilling mulching method and these were compared to un-mulching treatment a total of planted 92㎡ attheWol-aTestSiteForestattheForestforBiomaterialsResearchCenterinJinju-si, Gyeongsangnam-dofor 10monthsusing3-years-oldQuercusglaucaThunb. In comparison with the control site, the 60g/㎡ overlapping method was about 1.9 times higher than the root collar diameter, but there was no statistical significance between the treatments. Healthy seedlings were found to meet these conditions due to high biomass values and below and T/R ratios of 3.0 or lower and H/D ratios of 7.0 or lower. Comparing the values of LWR, SWR, and RWR, which can be evaluated for seedling due to the mulching treatments, as compared to the control, the growth of the ground areas including leaves and stems was enhanced, but the growth of the underground areas containing roots tended to have high control values. Based on this, the SQI value, which can be evaluated for the comprehensive quality of seedlings, was found to be significantly different between the control site and the mulching treatment sites, confirming that the growth and growth improvement effects were achieved with mulching treatments. The chlorophyll content analysis showed that there was a significant difference from the control site, and it was judged that weed generation in the control acted as an environmental stress, causing a decrease in chlorophyll content. It was found that the overlapping 80g/㎡ of polypropylene mulching material generated about 4 times fewer weeds than the control, and the manpower required for the mulching test field and weeding were equal at 3.3 people/100㎡/1 day. Mulching treatments have demonstrated a significant difference in the promotion of growth and quality of the seedlings and are judged as an alternative that can reduce the economic burden incurred by the purchase of the supplies and the manpower required to weed forestry plantations.

Comparison of Arthroscopic versus Mini Open Repair in Rotator Cuff Tear (회전근 개 파열에 대한 관절경적 봉합술과 소 절개 봉합술의 비교)

  • Park, Ji-Kang;Park, Kyoung-Jin;Kim, Yong-Min;Kim, Dong-Soo;Choi, Eui-Sung;Shon, Hyun-Chul;Cho, Byung-Ki;Im, Se-Hyuk
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.9 no.1
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    • pp.35-40
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    • 2010
  • Purpose: To compare the outcome of patients who underwent rotator cuff repair using all-arthroscopic mini-open repair techniques. Materials and Methods: We retrospectively reviewed 44 patients who underwent either arthroscopic (group I) or mini-open (group II) rotator cuff repair. 23 patients underwent an arthroscopic repair and 21 patients had a mini-open repair. The mean age was 50.4 years in the arthroscopic group and 56.7 years in the mini-open group. The outcomes for the 2 groups were evaluated using ROM, VAS, ASES, UCLA scale. Statistical analysis was performed using correlations, T-test, Paired T-test. The mean follow-up period in the arthroscopic and mini-open groups were 24.1months and 26.1months, respectively. Results: The group I (arthroscopic group) had 2 small-sized tears, 10 medium sized tears, and 11 large sized tears (3~5 cm). The group II (mini-open group) had 1 small sized tears, 8 medium sized tears, and 12 large sized tears. The mean cuff tear size of the group I and Group II were 3.8 cm and 4.2 cm, respectively. At last follow-up periods, ROM and functional scores were improved. In the group I and group II, there were no significant difference in ROM, VAS, ASES, UCLA score. Conclusion: The size of the tear did not produce different results at arthroscopic repair group but larger tear size was associated with a worse outcome in mini-open group. There were no significant clinical results between the arthroscopic and mini-open group.

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A comparative study of ADL and IADL of residential home and home for the aged dwelling elderly (노인의 거주 형태에 따른 일상생활동작(ADL) 및 도구적 일상 생활 동작(IADL)의 수행능력 비교)

  • Park, Chan-Eui;Chang, Chung-Hoon;Lee, Jae-Hyoung
    • The Journal of Korean Physical Therapy
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    • v.18 no.4
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    • pp.61-70
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    • 2006
  • Purpose: The purpose of this study was to investigate the activities of daily living (ADL) and instrumental activities of daily living (IADL) of residential home dwelling elderly and home for the aged dwelling elderly. In attempt to address medical professional caring the elderly, this comparative study examines the factors associated with dependence in the ADL and IADL in two samples of elderly people living in two different environments. Methods: The instrument of ADL and IADL widely used Katz ADL and IADL. Katz ADL and IADL was not a perfect fit for Korean. In concern with cultural factors Won developed K(Korean)-ADL and K-IADL scale reflecting Korean's own language expression and cultural factors in year of 2002. The assessment tool of this study was K-ADL and K-IADL. Differences of ADL and IADL were tested for statistical significance using group t-test and x2 test for comparisons between the residential home dwelling elderly and the home for the aged dwelling elderly. Results: Comparison of assessment for K-ADL and K-IADL in two different dwelling types was significant. Performance of ADL and IADL depend upon their living environment such as social status, number of children, income, present illness as well as age group. This study also showed significant differences of performance in some activities of ADL and IADL between the elderly who live in their own home and live in home for the aged. Comparison of performance of ADL and IADL in different dwelling types revealed that only one item of ADL was significant but only one item of IADL was not significant. It means that IADL is more difficult activities in the home for the aged dwelling elderly than the residential home dwelling elderly. The coupled elderly has more independent in some ADL and IADL activities compared with the single elderly. Conclusion: Using K-ADL and K-IADL is more convenient for Korean elderly. Medical professional consider some factors like dwelling style, social status, existing diseases and disabilities in order to care the elderly and train him/her activities of daily living as well as instrumental activities of daily living. Medical professional, especially physical and occupational therapist emphasize the training items which are bathing of ADL and grooming, housework, preparing meals, laundry, traveling, public transportation, shopping, using telephone and taking medicine of IADL based on the result of this study.

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Criteria of Evaluating Clothing and Web Service on Internet Shopping Mall Related to Consumer Involvement (인터넷 쇼핑몰 이용자의 소비자 관여에 따른 의류제품 및 웹 서비스 평가기준에 관한 연구)

  • Lee, Kyung-Hoon;Park, Jae-Ok
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.12 s.159
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    • pp.1747-1758
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    • 2006
  • Rapid development of the information technology has influenced on the changes in every sector of human environments. One prominent change in retail market is an increase of electronic stores, which has prompted practical and research interest in the product and store attributes that include consumer to purchase products from the electronic shopping. Therefore many marketers are paying much attention to the criteria of evaluating clothing and web service on internet shopping malls. The purpose of this study is to examine differences of clothing and web service criteria of consumer groups (High-Involvement & High-Ability, Low-Involvement & High-Ability, High-Involvement & Low-Ability, and Low-Involvement & Low-Ability) who are classified into consumer involvement and internet use ability. The subjects of this study were 305 people aged between 19 and 39s, living in Seoul and Gyeonggi-do area, and having experiences in buying products on the internet shopping. Statistical analyses used for this study were the frequency, percentage, factor analysis, ANOVA and Duncan test. The results of this study were as follows: Regarded on the criteria of evaluating clothing, the low different groups had significant differences in the esthetic, the quality performance and the extrinsic criterion. Both HIHA group and HILA group showed the similar results. They considered every criterion of evaluating clothing more important, compared with other groups. Regarded on the criteria of evaluating web service related to the low different groups, there were significant differences in the factors related to the shopping mall reliance, the product, the satisfaction after purchase, and the promotion and policy criterion. Both HIHA group and HILA group showed the similar results as well. They considered every criterion of evaluating web service more important, compared with other groups. In conclusion, HI groups perceive relatively more dangerous factors which can be occurred during internet shopping. Therefore, internet shopping malls need to provide clothing that can satisfy the HI groups as well as make efforts to remove the dangerous factors on the internet.

Research on the Effect of the Control Methods of Irrigation Water on the Growth and Yield of Paddy Rice. (한발기에 있어서 용수관리 방법이 수도생육과 그 수량에 미치는 영향에 관한 연구)

  • 김시원
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.13 no.1
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    • pp.2177-2190
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    • 1971
  • This experiment was made to determienthe effect of various soil moisture contents in simulated drought conditions on different stages of rice growth. The drought conditions were developed at such three rice-growing stages as transplanting, immediately after transplanting and young ear forming. Three different lengths of drought periods, which are ten days, twenty days and thirty days, were applied for each growing stage of rice. The rice variety used this experiment is Nong-rim 29. This experiment was conducted at the university farm of the Kon-Kuk University during the period of $1968{\sim}1970$. Three reprications for each of 12 treatments and split plot design were employed in this study. Bottomless wood square boxes, $1^m{\times}1^m{\times}1^m$, were burried in the test plot and box top was covered with poloyethylene sheets to avoid natural rainfall drops. Standard plots were irrigated continuously with a water depth of 40mm/day and those of drought treatments were irrigated continuously up to the beginning of the planned drought period, and they were irrigated again with a depth of 40mm/day up to the maturing stage of rice. Other methods for rice raising followed those methods developed by the Field Crops Experiment Station of the Office of Rural Development. During this experiments, climatic conditions in regard to rainfalls, sunshine hours, and temperatures were observed. According to this observation, those values measured deviate slightly from the annual means. However the growing condition of rice plants were normal. The pH value of irritation water is nearly neutral, and soils in the test plots are relatively fertile, being similar to ordinary paddy soils. Analysis of variances for number of stalks, plan-height, ear sprouting date, length of stalks, ear length, number of ears per plant, fertility, grain weitght, weight of plant, and yield were carried out. The variances for plant height, ear sprouting date, length of stalk ear length, and yield has statistical significance under drought treatments applied at three different growing stages. The variance showing the effect of lengths of drought period is highly significant for all the treatments studied except that of grain weight. The interaction between drought periods and drought treatments at different growing stages is significant for plant height, stalk length, ear length, number of ears, fertility and yield, these results indicated that droughts at different growing stages have influence on plant height, ear length, yield, and length of drought period also has strong influence on all factors studied except grain weight. The combination of drought treatments at different rice growing stages and lengths of drought periods has different effects on various agronomic characteristics, including yield. Plant height under drought treatment practiced at transplanting stage is the lowest, and drought treatment applied immediately after transplanting resulted in the least number of stalks. The effect of different lengths of drought periods on plant height and number of stalks depends signis ficantly on increasing days of drought. Ear sprouting date tends to be delayed for one or two days undedrought treatments at transplanting period and with increasing days of drought. Better yield is secured in drought treatment applied immediately after transplanting. Adverse effect war observed when drought treatment was applied at ear forming period. These effects may be attributed to the alternation of irrigation and drought causing vigorous root activity. In general, yield linearly decreases as the length of the drought period increases. The results obtained in this study demonstrate that, in order to mimimize damage due to drought, and, to save irrigation water, paddy fields, immediately after transplanting, may be not irrigated, since there is sufficient moisture in the soil, and that sufficient irrigation water should be applied again in the ear forming stage of rice plant.

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A Study on Awareness of Automated External Defibrillator, Usage Intention and Related Educational Experience in Workers at Public Institutions (공공기관 종사자들의 자동제세동기에 대한 인식과 시행의도 및 교육경험에 관한 연구)

  • Kim, Mu-Nui;Lee, Hyeon-Ji
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.11
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    • pp.416-424
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    • 2017
  • This study was conducted to examine the awareness of workers in public institutions of automated external defibrillators, their usage intention and related educational experience in an effort to increase the efficiency of education and the rate of automated external defibrillator usage in emergency situations. The subjects in this study were 243 selected. male and female adults who worked in public institutions in Gangwon Province. A survey was conducted from June 13 to August 21, 2016. The statistical analysis was based on the frequency analysis and the $X^2$-test. There were significant differences among the public institution workers awareness of how to use an automated external defibrillator according to gender (${\chi}^2=6.32$, p<0.05) and academic credentials (${\chi}^2=5.91$, p<0.05). Additionally, there were significant differences in usage intention according to academic background (${\chi}^2=5.70$, p<0.05). The most common reason for having no intention to use an automated external defibrillator for patients with cardiac arrest was that the respondents did not know how to use it (31.5%). There were also significant differences in educational experience with automated external defibrillators according to age (${\chi}^2=6.15$, p<0.05), academic credentials (${\chi}^2=11.56$, p<0.01) and career (${\chi}^2=11.92$, p<0.01). The most common form of education that the workers received pertaining to automated external defibrillators was a combination of theoretical and practical education, which represented 55.9%. The findings of the study seem to suggest that workers in public institutions used by many people must receive compulsory standard education regarding automated external defibrillators and try to boost the revival rate of patients with cardiac arrest in real emergency situations.

The Identification of the High-Risk Pregnacy, Usign a Simplified Antepartum Risk-Scoring System (단순화된 산전위험득점체계를 이용한 고위험 임부의 확인)

  • Jo, Jeong-Ho
    • The Korean Nurse
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    • v.30 no.3
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    • pp.49-65
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    • 1991
  • This study was carried out to assess the problems with the pregnant women, and check out the risk-factors in the high-risk pregnancies, using a simplified antepartum risk-scoring system, which was revised from Edwards' scoring system to be suitable for Korean situaition. This instrument was included 4 categories, demographic, obstetric, medical and miscellaneous factors. This survey was based on the 1300 pregnant women who were admitted, $x^2$-test, F-test, Pearsons correation, using statistical package SAS in NAS computer system, KIST. The results of the study were as follows; 1. 1313 infants were deliveried of these 560 infants(42.7%) were born to mothers with risk-scores > 7, and 753 infants(57.3%) were born to mothers risk-scores <7. 2. Maternal age" parity, education level, of the demographic factors were significant relation statistically to identify the high risk pregnancies($X^2$=20.88, 42.87, 15.60 P < 0.01). 3. C-section, post term, incompetent cervix, uterine anomaly, polyhydramnios, congenital anomaly, sensitized RH negative, abortion, preeclampsia, excessive size infant, premature, low birth weight infanl, abnormal presentation, perinatal loss, multiple pregnancy, of the obstetric factors were significant relation statistically to identify the high risk-pregnancies. ($X^2$ = 175.96, 87.5, 16.28, 21.78, 9.46, 8. 10, 6.75, 22.9, 64.84, 6.93, 361.43, 185.55, 78.65, 45.52, P < 0.01). 4. Abnormal nutrition, anemia, UTI, other medicalcondition(pulmonary disease, severe influenza), heart disease, V.D., of the miscellaneous and medical factors, were significant relation statistically to identify the high risk-pregnancies. 5. Premature, low birth weight infant, contracted pelvis, abnormal presentation, of the risk factors were significantly related with Apgar score at 1 '||'&'||' 5 minute after birth and neonatal body weight. 6. Apgar score at 1 '||'&'||' 5 minute after, birth and neonatal body weight were significantly negative correlated with risk-score. 7. There were statistically significant difference between risk-score and Apgar score at 1 '||'&'||' 5 minute after birth, 3 group(0-3, 4-6, above 7), and neonatal body weight, 2 group(below 2.5kg, the other group) (F=104.65, 96.61, 284.92, P<0.01). 8. Apgar score at 1 '||'&'||' 5 minute after birth(below 7), and neonatal body weight(below 2.5kg), were significant relation statistically with risk score.($x^2$=65.99, 60.88, 177.07, P<0.01) were 60.8 %, 60% . 9. Correct classifications of morbid infants(l '||'&'||' 5 minute Apgar score < 7) were 77.8%, 83.8% and that of nonmorbid infants(l '||'&'||' 5 minute Apgar score > 7) were 60.8%, 60%. 10. There were statistically significant difference between dislribution of maternal risk-score among the morbid infants(l '||'&'||' 5 minute Apgar score < 7) and non morbid infants(l '||'&'||' 5 minute Apgar score> 7) ($x^2$=64.8, 58.8, P < 0.001). 11. There were statistically significant difference between distribution of morbid infants(l '||'&'||' 5 minute Apgar score < 7) and fetal death. 12. The predictivity for classifying high.risk cases was 12 % and for classifying low-risk cases was 98.3 % in 5 minute Apgar score. Suggestions for further studies are as follows; 1. Contineous prospective studies, using this newly revised scoring system are strongly recommended in the stetric service. 2. Besides risk facto~s used in this study, assessmenl of risks by factors in another scoring system and paralled studies related to perinatal outcome are strongly recommended.

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Research on a Biennale Visitors' Pursuing Benefit -Centering on the Gwangju Biennale- (비엔날레 참관자의 추구편익이 행동의도에 미치는 영향 연구 -광주비엔날레를 중심으로-)

  • An, Tai-Gi;Kim, Hee-Jin
    • The Journal of the Korea Contents Association
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    • v.9 no.11
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    • pp.432-442
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    • 2009
  • This research had a look at what effect of the pursing benefit has on satisfaction, behavioral intention, and attitude of the visitors to the Gwangju Biennale. The survey was conducted for 320 visitors who finished their exhibition viewing schedule starting September 5 until September 19 [15 days]. 300 questionnaires excepting 20 unfaithfully responded copies among those collected from the surveyed were used for the analysis. As for the statistical disposal of the collected data, after going through the process of Data Coding, this research conducted an frequency analysis using SPSS 12.0 for window & statistics package program AMOS 5.0, an exploratory factor analysis to test the reliability and feasibility of the data, and reliability test of each factor; then, this research tested a hypothesis using structural equation model. The research results are as follows: First, as a result of factor analysis of the 15 pursuing benefits, 4 factors were elicited, such as pursuit of an intellectual experience, pursuit of a novel, exotic experience, pursuit of interpersonal, cultural exchange, and pursuit of internal fullness, etc.; as a result of factor analysis of the 10 attitudes, three factors were elicited, such as affective, cognitive, behavioral factors; as a result of factor analysis of 12 types of satisfaction, two factors, such as satisfaction with facilities and convenience matters, etc. were elicited. Second, as a result of the suitability of research model, suitability, its fidelity came out as $x^2=107.508$, d.f.=48, p=.000, Q=2.240, GFI=.942, AGFI=.906, RMR=.024, NFI=.952, TLI=.963, CFI=.973, RMSEA=.064. Third, pursuing benefit was found out to have a positive effect on satisfaction, attitude, and behavioral intention. Fourth, attitude was found out to have a positive significant effect on satisfaction. Fifth, attitude was found out to have a positive effect on behavioral intention. Sixth, satisfaction was found out to have a positive effect on behavioral intention.

Ultrasound-Guided Local Steroid Injection Therapy for Acute Calcific Tendinitis of Shoulder (초음파를 이용한 급성 극상근 석회화 건염의 스테로이드 국소 주사 요법)

  • Kim, Jung-Man;Nam, Ho-Jin;Ra, Ki-Hang;Kang, Min-Ku
    • The Journal of Korean Orthopaedic Ultrasound Society
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    • v.2 no.2
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    • pp.85-89
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    • 2009
  • Purpose: To analyze the clinical outcome after ultrasound guided multiple dry needlings and local steroid injection for acute calcific tendinitis of shoulder. Materials and Methods: Twenty patients with acute episode of pain by calcific tendinitis of shoulder with average age 58.2 (50~70 years) and follow-up of 18 months in average (range, 12~24) were included in study. There were 18 patients with right and 2 with left sided involvement. All patients had calcific deposits in the supraspinatus tendon. All patients underwent standardized nonoperative treatment protocol, consisting of 5~12 MHz high resolution ultrasound guided multiple dry needlings with 18 guage needle, followed by 2% lidocaine 1cc and 40 mg/ml depomedrol 1cc injection at site of calcific tendinitis. The outcome was assessed by UCLA shoulder score, range of motion and VAS score. A statistical analysis with ANOVA and Tukey's post-hoc test with the significance level at 5% was performed using SAS 9.1 software (SAS Institute, Cary, NC). Results: All patients got continuous relief of pain right after the procedures until final follow-up. Before the procedures, the UCLA scores were fair in 15 patients and poor in 5. After the procedures, the UCLA scores were excellent in 16 patients and good in 4. All cases revealed no limitation of shoulder function. The average VAS score decreased from 8.9 before the procedures to 0.5 at final follow-up (p<0.0001). No complication was encountered. Conclusion: An ultrasound guided local steroid injections following multiple dry needlings would be one of the useful treatment modality for the acute calcific tendinitis of shoulder.

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