• Asian Pacific Journal of Cancer Prevention
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• 제15권22호
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• pp.9673-9678
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• 2014

Background: Breast cancer is a fatal disease and the most frequently diagnosed cancer in women with an increasing pattern worldwide. The burden is mostly attributed to metastatic cancers that occur in one-third of patients and the treatments are palliative. It is of great interest to determine factors affecting time from cancer diagnosis to secondary metastasis. Materials and Methods: Cure rate models assume a Poisson distribution for the number of unobservable metastatic-component cells that are completely deleted from the non-metastasis patient body but some may remain and result in metastasis. Time to metastasis is defined as a function of the number of these cells and the time for each cell to develop a detectable sign of metastasis. Covariates are introduced to the model via the rate of metastatic-component cells. We used non-mixture cure rate models with Weibull and log-logistic distributions in a Bayesian setting to assess the relationship between metastasis free survival and covariates. Results: The median of metastasis free survival was 76.9 months. Various models showed that from covariates in the study, lymph node involvement ratio and being progesterone receptor positive were significant, with an adverse and a beneficial effect on metastasis free survival, respectively. The estimated fraction of patients cured from metastasis was almost 48%. The Weibull model had a slightly better performance than log-logistic. Conclusions: Cure rate models are popular in survival studies and outperform other models under certain conditions. We explored the prognostic factors of metastatic breast cancer from a different viewpoint. In this study, metastasis sites were analyzed all together. Conducting similar studies in a larger sample of cancer patients as well as evaluating the prognostic value of covariates in metastasis to each site separately are recommended.

• Journal of Periodontal and Implant Science
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• 제44권1호
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• pp.8-12
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• 2014

Purpose: The aim of this retrospective chart review was to evaluate the four-year survival rate of a titanium implant system. Methods: A total of 352 sand-blasted, thermally acid-etched titanium implants were inserted into 181 partially or completely edentulous patients. Their cumulative survival rate was evaluated retrospectively. Associated factors, such as the implant distribution and treatment type were included in the evaluation. Results: The implants were equally distributed between the maxilla (52.3%) and the mandible (47.7%). 48 implants (13.6%) were placed in the anterior region and 304 implants (86.4%) in the posterior region. The majority of the implants were inserted into bone of type II and III quality (89.8%) and volume (quantity B and C, 87.2%). Most of the implants (70.7%) were restored as single crowns; 28.7% supported a bridge construction and 0.6% a full denture. Only one implant failed, resulting in a four-year cumulative survival rate of 99.7%. Conclusions: The implant system showed an excellent four-year survival rate. It proved to be a safe and predictable means for restoration of the dentition in partially or completely edentulous patients.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6687-6692
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• 2013

Background: This study aimed to determine the demographical distribution, survival and prognostic factors for neuroendocrine tumors monitored in our clinic. Materials and Methods: Data for 52 patients who were admitted to Cumhuriyet University Medical Faculty Training Research and Practice Hospital Oncology Center between 2006 and 2012 and were diagnosed and treated for neuroendocrine tumors were investigated. Results: Of the total, 30 (58%) were females and 22 (42%) were males. The localization of the disease was gastroenteropancreatic in 29 (56%) patients and other sites in 23 (44%). The most frequently involved organ in the gastroenteropancreatic system was the stomach (n=10, 19%) and the most frequently involved organ in other regions was the lungs (n=10, 19%). No correlation was found between immunohistochemical staining for proteins such as chromogranin A, synaptophysin, and NSE and the grade of the tumor. The patients were followed-up at a median of 24 months (1-90 months). The three-year overall survival rate was 71%: 100% in stage I, 88% in stage II, 80% in stage III, and 40% in stage IV. The three-year survival rate was 78% in tumors localized in the gastroenteropancreatic region, and 54% in tumors localized in other organs. In the univariate analysis, gender, age, performance status of the patients, grade, localization, surgical treatment, and neutrophil/lymphocyte ratio (${\leq}5$ versus >5) affected the prognosis of the patients. Conclusions: Most of the tumors were localized in the gastroenteropancreatic region, and the three-year survival rate in tumors localized in this region was better than the tumors localized in other sites. Surgical treatment was a positive independent prognostic factor, whereas Grade 3 and a neutrophil/lymphocyte ratio of >5 were negative independent prognostic factors.

• Communications for Statistical Applications and Methods
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• 제26권6호
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• pp.623-633
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• 2019

This paper proposes two distance measures between two cumulative hazard functions that can be obtained by comparing their difference and ratio, respectively. Then we estimate the measures and present goodness of t test statistics. Since the proposed test statistics are expressed in terms of the cumulative hazard functions, we can easily give more weights on earlier (or later) departures in cumulative hazards if we like to place an emphasis on earlier (or later) departures. We also show that these test statistics present comparable performances with other well-known test statistics based on the empirical distribution function for an exponential null distribution. The proposed test statistic is an omnibus test which is applicable to other lots of distributions than an exponential distribution.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.526-526
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• 2023

Water circulation plays a crucial role in regulating the salinity of estuaries, which is essential for the survival of estuarine organisms. Changes in freshwater inflows or sea level can have significant impacts on the distribution and abundance of species within these ecosystems. To better understand these dynamics, this paper presents a study of water circulation and salinity distribution in Seomjin River estuary using the Finite Volume Coastal Ocean Model (FVCOM) numerical model. An extreme scenario was simulated to assess the potential impact of tidal currents and river flow discharge on circulation and salinity distribution. The results of this study have important implications for managing estuarine ecosystems and conserving their associated biodiversity.

• Nonlinear Functional Analysis and Applications
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• 제28권3호
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• pp.793-800
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• 2023

In this paper, we propose a generalization of Lindley distribution (GLD) via a special structure that is concern with progressively Type-II right censoring and time failure data. We study the modern properties that we have built by such combination, for example, survival function, hazard function, moments, and estimation by non-Bayesian methods. Application on some selected data related to Lindley distribution (LD) and (ED) have been employed to find out the best distribution that can fit data comparing with the GLD.

• 유통과학연구
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• 제20권6호
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• pp.57-66
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• 2022

Purpose: Business agility is an important key to survival for SMEs in Indonesia, especially during the COVID-19 pandemic. Indonesian local product distribution and service distribution are mostly served by SMEs. Agile businesses will be able to assist them in the proper distribution of products and services. This research examines how the direct and indirect influence of IT capabilities on business agility through organizational learning and business intelligence for small and medium enterprises in the distribution of Indonesian products and services. Research design, data and methodology: This research uses SEM method with SmartPLS tool. The sample of this research was conducted on small and medium enterprises in the distribution of Indonesian products and services. The sample obtained in this study was 202 SME owners or managers (strategic level). Results: Business intelligence plays a key role in improving business agility. The results of IT capability can directly and indirectly affect business agility through organizational learning. Conclusions: Business intelligence has the biggest role in increasing business agility in SMEs in Indonesia. IT capability has an indirect effect on business agility through organizational learning. The findings of this study prove that IT capabilities do not indirectly affect business agility through business intelligence.

• 유통과학연구
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• 제16권12호
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• pp.81-93
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• 2018

Purpose - The purpose of this study was to propose a specific and empirical continuous transaction strategy through service quality of improvement to small and medium Korean companies whose main business is B2B distribution and sale of general-purpose SW. Research design, data, and methodology - The research procedure is largely divided into two phases. In the first phase, the service quality, the customer satisfaction, and the continuous transaction research hypothesis and the verification are carried out. Experimental data were collected from 450 companies, CEO companies of SMEs innovation institutes, and 510 companies from medium and large enterprises. From September 15 to October 5, 2015, 215 questionnaires were used. And research hypothesis and test were conducted by SPSS SW Ver. 20. Results - The results of the study confirm that service quality has a positive effect on customer satisfaction and continuous transaction: as the detailed items for improving the service quality, 'responsiveness', 'assurance' and 'empathy' have been adopted. Therefore, there are critical factors of a company's survival through continuous transaction. Conclusions - Through this study, we confirmed that the survival of small businesses require continuous improvement in service quality. Among the factors improving service quality, empathy means service satisfaction of customers; so, it is necessary to continuously improve it by evaluating customer satisfaction. Responsiveness means rapid response to customer needs and reliability; it is necessary to enhance customer responsiveness by continuous job training and service training. Finally, assurance is the same as sales product or after service. This means that it is necessary to not only issue the "supply contract," but also improve the reliability of the sales product by securing the competence of the consulting professional. However, because the service quality measurement factors selected in this study are the measurement factors that are mainly applied to large companies or those in the service industries, it is important to consider the type of sales of software distribution companies.

• 한국도로학회논문집
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• 제12권1호
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• pp.61-69
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• 2010

본 연구에서는 신뢰성 개념을 도입하여 최근 10년간의 수원과 의정부 지역의 일반국도 아스팔트 포장구간의 수명 데이터를 기반으로 적합한 모수적 수명분포 선정과 헤저드 함수 및 생존확률을 추정하였다. 최적 수명분포형을 찾기 위해 확률지 개념을 이용하여 모수를 추정하였으며 적정 확률분포형태의 결정은 Anderson-Darling 통계값을 이용하였다. 그 결과 분석 대상 지역 포장의 수명 데이터를 가장 잘 설명하는 수명분포는 대수정규(Lognormal)분포인 것으로 분석되었다. 또한 본 연구에서 제안한 대수정규분포에 의해 추정된 생존확률함수는 실제 관측값과 차이가 거의 없음을 확인하였다. 본 연구에서 제안한 신뢰성 개념을 이용한 분석 방법은 포장관리 및 유지보수 데이터가 축적되어감에 따라 비교적 용이하게 계속 update가 가능하며 따라서 보다 정확한 포장수명에 대한 신뢰도 값에 접근해 갈 수 있는 이점이 있다.

• Journal of the Korean Statistical Society
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• 제23권2호
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• pp.349-365
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• 1994

We develop in this paper the likelihood ratio test (LRT) for testing $H_1 : F_1 \preceq F_2$ against $H_2 - H_1$ where $H_2$ imposes no restriction on $F_1$ and $F_2$ and '$\preceq$' means failure rate ordering. Both one and two-sample problems will be considered. In the one-sample case, one of the two distributions is known, while we assume in the other case both are unknown. We derive the asymptotic null distribution of the LRT statistic which will be of chi-bar-square type. The main issue here is to determine the least favorable distribution which is stochastically largest within the class of null distributions.