• 상하수도학회지
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• 제22권6호
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• pp.647-655
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• 2008

Sewer Rehabilitation Project (SRP) is planed, designed and constructed to perform its intended performance as sewerage delivery systems. Recently, a subject of performance evaluation methodology development for SRP has become a great deal of concern among researchers in Korea. From the view point of Sewage Treatment Plant (STP), however, the estimation of improvement efficiency for SRP is in lack of reliability due to the fact that affections for the treatment efficiency and operating condition are not reflected on SRP design and construction. In this study, statistical methodology was used in the analysis of data, which are taken during 1,186 days ($1^{st}$ Jan. 2005 - $31^{th}$ Mar. 2008) from the influent, effluent and operating conditions of full-scale STP($25,000m^3/d$). Then the effect of SRP on the influent characteristics and operating conditions changing was compared and evaluated. Results from the statistical evaluation show that SRP causes characteristic changes in influent and exerts a significant effect especially on the performance of STP.

• 응용통계연구
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• 제32권2호
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• pp.173-185
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• 2019

과학적 연구에서 핵심적인 연구 주제 또는 가설은 대부분 인과적 질문(causal question)을 포함한다. 예를 들어, 전염병 예방을 위한 치료법의 효과 연구, 특정 정책의 시행으로 인한 효용(utility)의 평가에 대한 연구, 특정 사용자를 대상으로 노출된 광고의 종류에 따른 광고의 효과성에 대한 연구는 모두 인과 관계(causal relationship)의 추론이 요구된다. 이러한 인과 관계를 다루는 통계적 인과 추론(statistical causal inference)의 주요 관심사 중 하나는 모집단에 일종의 개입(정책 혹은 처치)을 적용한 후 개입의 효과를 정확하게 추정하는 것이다. 인과 추론은 임상실험과 정책결정에서 주로 이용되었으나, 이른바 빅데이터 시대의 도래로 가용한 관측자료가 폭발적으로 증가하였고 이로 인하여 인과 추론에 대한 잠재적 응용가치와 수요가 지속적으로 증가하고 있다. 하지만 가용한 대부분의 자료는 임의실험 기반의 자료와 달리 개입이 임의로 분배되지 않은 비실험 관측자료이다. 따라서, 본 논문은 비실험 관측자료로부터 개입의 효과를 추정하기 위한 인과 추론의 핵심 개념과 최근의 연구동향을 소개하고자 한다. 이를 위하여 본문에서는 먼저 개입의 효과를 Neyman-Rubin의 잠재 결과(potential outcome) 모형으로 나타내고, 개입의 효과를 추정하는 여러 접근법 중 특히 성향점수(propensity score) 기반 추정법과 회귀모형 기반 추정법을 중점적으로 소개한다. 최근 연구동향으로는 (1) 평균 효과 크기 추정을 넘어선 개인별 효과 크기의 추정, (2) 효과크기 추정에 있어서 자료 규모의 증대로 인한 차원의 저주가 야기하는 난제들과 이에 대한 해결방안들, (3) 복합적 인과관계를 반영하기 위한 Pearl의 구조적 인과 모형(structural causal model) 및 잠재 결과 모형과의 비교의 3가지 주제로 구분하여 소개한다.

• Imaging Science in Dentistry
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• 제33권4호
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• pp.223-229
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• 2003

Purpose: To compare the effects of the conservative treatment and operative treatment by observation of osseous changes of the TMJ and mandibular asymmetry in condylar fracture patients. Materials and Methods: 33 condylar fracture patients (17 with conservative and 16 with operative treatment) were included in this study. After a minimum of 6 months after the surgical procedure, patients were given a follow up examination of the osseous changes using a transcranial view. Differences in the osseous changes of both groups were compared and the asymmetry indices were calculated on a postero-anterior skull view. Results: The TMJ of the operative treatment group showed more significant osseous changes than the conservative treatment group. The affected TMJ showed more significant osseous changes than the unaffected TMJ in the both groups. The unaffected TMJ of the conservative group and the affected TMJ of the operative group showed significant osseous changes. The mandibular asymmetry indices in the conservative and operative group were 5.12 and 7.30 respectively at the time of treatment, and 2.39 and 3.41 respectively at the follow-up. But the mandibular asymmetry between the both groups showed no statistical differences. Conclusion: The TMJ of the operative group showed more significant osseous changes than the conservative group, but the mandibular asymmetry between the both groups showed no statistical difference.

• 한방재활의학과학회지
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• 제23권4호
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• pp.1-7
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• 2013

Objectives The purpose of this study is to compare the effects of ShinBaro pharmacopuncture and Jungsongouhyul pharmacopuncture on whiplash injury by traffic accident. Methods This study was carried out on 30 patients who received treatment in Jaseng Hospital of Korean Medicine. 30 patients were divided ShinBaro pharmacopuncture group and Jungsongouhyul pharmacopuncture group. Visual analog scale (VAS) and neck disability index (NDI) were compared after treatment. Results 1) Both the ShinBaro group and Jungsongouhyul group showed significant improvement in the visual analog scale (VAS) and neck disability index (NDI) after 3 weeks of treatment. 2) The VAS and NDI of the ShinBaro group decreased gradually with treatment. The VAS scores showed significant improvement up to week 2, but although week 3 showed further improvement compared to week 2, the difference did not reach statistical significance. The NDI scores showed significant improvement consistantly throughout the treatment period. 3) The VAS and NDI of the Jungsongouhyul group decreased with treatment also. The VAS scores significantly improved up to week 2, but though week 3 showed further improvement in comparison to week 2, the difference did not reach statistical significance. The NDI scores showed significant improvement consistantly throughout the treatment period. 4) Although the ShinBaro group showed a swifter decline than the Jungsongouhyul group in both VAS and NDI scores, the difference was not statistically significant. Conclusions We found out that ShinBaro pharmacopuncture group and Jungsongouhyul pharmacopuncture group is effective and useful in whiplash injury by traffic accident. And, further studies will be needed.

• The Journal of Korean Physical Therapy
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• 제15권3호
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• pp.388-411
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• 2003

The purpose of this study has been conducted to reduce the lower limbs' spasticity of the patients with hemiplegia caused by cerebral stroke of apoplexy and find differences about spasticity effects among each group. The objects of this study covered 24 patients with hemiplgia who are either in the oo hospital in Daegu or under treatment from home to hospital. The objects fall into three groups which are a group of neurological development treatment, a group of functional stimulus treatment and a group of neurological development treatment and functional stimulus treatment. The result of this study were as follows : 1) The neurological development treatment has been found to reduce the lower limbs' spasticity of patients with hemiplegia caused by cerebral stroke of apoplexy and compared to before-treatment, the MAS value of spasticity has been shown to be statistically meaningful ,and gradually over the period of between 4 weeks and 8 weeks(P <.05). 2) The functional electric stimulus treatment has been shown to reduce the lower limb's spasticity of patients with hemiplegia caused by cerebral stroke of apoplexy and compared to before-treatment, the MAS value of spasticity was statistically meaningful and compared to 4 weeks, even at the time of 8 weeks, the MAS value of spasticity have shown statistical meaningness. (P <.05) 3) When neurological development treatment and functional electric stimulus treatment was applied at the same time, the lower limbs' spasticity of patients with hemiplegia was reduced meaningfully(P <.05). Compared to before-treatment at the time of 4 weeks, the MAS value of spasticity was statistically meaningful and compared to 4 weeks at the time of 8 weeks the MAS value of spasticity was also statistically meaningful(P <.05) 4) In the case of time-based MAS value of each group, functional electric stimulus treatment reduced the spasticity more meaningfully than neurological development treatment, and the group of same application of functional electric stimulus treatment and neurological development treatment showed better statistical meaningness than functional electric stimulus treatment alone(P <.05) and finally the group of same application of neurological development treatment and functional electric stimulus treatment showed more meaningful difference than neurological development treatment alone(P <.05)

• 한국학교보건학회지
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• 제6권1호
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• pp.9-44
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• 1993

An explorative and descriptive study in order to determine the effect of family structure and other socio-demographic variables on health behavior, belief, locus, and value and utilization of public health service was carried out. Data were collected from 1,653 subjects randomly sampled in three areas, Seoul, Kyunggi province, and Cheju province. From Seoul 849 subjects were selected, 397 subjects Kyunggi, and 407 subjects from Cheju, respectively. Self-reporting questionaires were administered during the period from March to June, 1992. The major findings were as follows: 1) The subjects visited herb-doctor's at irregular intervals mainly to have tonic medicine prepared. They preferred herb-doctor's rather than with doctors at clinics and hospitals. Statistically significant difference was found among the regions studied (p<0.05). 2) The reason for visiting hospitals was primarily for treatment of diseases. They preferred hospital because they felt that the hospitals offer much highly reliable treatment services as well as medical accessibility. For the purpose of hospital utilization, statistically significant differences existed among sex, educational level, family type and region. However, no significance was found among sex, educational level, and region (p<0.05). 3) The subjects utilized general hospitals mainly for diagnosis and treatment of diseases. They preferred general hospitals because of their much better facilities and reliability. Statistical significance was found among sex, educational level, and region (p<0.05). 4) The subjects visited dentist at irregular intervals basis. They visited once half a year or three to four months. their purpose of visit was mainly for diagnosis and treatment of diseases. Statistical significance differences were found among educational level, region and economic standard (p<0.05). 5) Whenever their illnesses were mild and the pharmacies was located in nearby they visited to pharmacies. They visited once a month and patient medicines. Statistically significant differences were found among sex, educational level and region (p<0.05). 6) The subjects believed that herb medicine was quite efficacious for treatment of some diseases, particularly by information handed down through time-honored tradition and experience. However, they recognized that the efficacy of folk medicine can vary with type and severity of diseases. Statistical significance was among sex, educational level, region and economic standard (p<0.05). 7) The reason why subjects believed that pray and superstition are effective for treatment of certain type of diseases, particularly in neuropathy, was the belief in God's almighty. Statistically significant differences were found among sex, educational level, regions and economic standard (p<0.05). 8) Most of subjects under same condition preferred western medicine because they believed that it is more scientific and prompts in showing therapeutic effect. Statistical significance was not found in the choice of type of public health service among, regions. But significant differences were found among sex, educational level and region (p<0.05). 9) The subjects looked for pharmacy if they thought the symptom was mild. However, they visited hospitals for chronic disease and general hospitals for emergency treatment. Statistical significances were found among educational level, region and economic standard (p<0.05). 10) Although most of students wanted to have a healthy life as for the component of health standard and value, they think that they are not healthy (p<0.05). As for the health behavior, significant difference was found in the proportion of smoking and drinking between educational level and region (p<0.05). The health locus was affected by educational level, and health behavior was influenced by region, sex and educational level. The utilization of type of public health service was influenced by family type and region, and health belief by region and educational level, and the health values by region and economic standard respectively, most of correlation showed statistical significance. Among them, the highest correlation was seen between locus of control and external/internal locus of control, which is quite obvious. The correlation between health belief and behavior was the next highest, but still low (0.343). All the other variables are low but significant except only a few of those. These findings indicate that health education should be incorporated into the curriculum so as to develop desirable health habit, and ability of self-control in accordance with their growth stages. A systematic and scientific understanding on the herb/folk medicine is needed, and greater reliability of the utilization of public health services are is still required. Health policy for equal distribution of health service throughout the country along the hierarchical health service system and complementary mutual assistance and cooperation among various health organizations are also required.

• Communications for Statistical Applications and Methods
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• 제15권5호
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• pp.727-735
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• 2008

Consider a clinical trial in which the main end-point is survival. Suppose after the start of the study an intermediate event occurs which may be influenced by a covariate(or treatment). In many clinical studies the occurrence of an intermediate event may change the survival distribution. This investigation develops two-stage model which, in the first stage, models the effect of covariate on the intermediate event and models the relationship between survival time and covariate as well as the intermediate event. In this paper, the two-stage model is presented in order to model intermediate event and a test based on this model is also provided. A numerical simulations are carried out to evaluate its overall significance level.

• Communications for Statistical Applications and Methods
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• 제25권3호
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• pp.275-282
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• 2018

This paper discusses the use of projections for the sums of squares in the analyses of variance for two-way nested design data. The model for this data is assumed to only have random effects. Two different sizes of experimental units are required for a given experimental situation, since nesting is assumed to occur both in the treatment structure and in the design structure. So, variance components are coming from the sources of random effects of treatment factors and error terms in different sizes of experimental units. The model for this type of experimental situation is a random effects model with more than one error terms and therefore estimation of variance components are concerned. A projection method is used for the calculation of sums of squares due to random components. Squared distances of projections instead of using the usual reductions in sums of squares that show how to use projections to estimate the variance components associated with the random components in the assumed model. Expectations of quadratic forms are obtained by the Hartley's synthesis as a means of calculation.

• Communications for Statistical Applications and Methods
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• 제12권3호
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• pp.705-712
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• 2005

Biplot is a graphical display of the rows and columns of an n${\times}$p data matrix. In particular, Gabriel (1995) suggested the MANOVA biplot using singular value decomposition (SVD) with the averages of response variables according to treatment groups. But his biplot may cause wrong results by disregarding them when there exist covariate effects. In this paper, we will provide the MANCOA biplot based on the SVD with the parameter estimates for MANCOVA model when there exist covariate effects.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2000년도 추계학술발표회 논문집
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• pp.27-32
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• 2000

To overcome boundary problems with wavelet regression, we propose a simple method that reduces bias at the boundaries. It is based on a combination of wavelet functions and low-order polynomials. The utility of the method is illustrated with simulation studies and a real example. Asymptotic results show that the estimators are competitive with other nonparametric procedures.