• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권6호
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• pp.518-528
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• 2008

Purpose: The long-term experience of using osseointegrated implants for prosthetic rehabilitation of the edentulous patients shows that high success rates can be predictably achieved. Primary implant stability has been identified to be a prerequisite to achieve osseointegration. In this study, we set up the amount of removed bone so that it differed on implant installation site for each group. The influence of each initial stability on secondary stability and osseointegration was compared with time lapse using resonance frequency analysis and histomorphometric analysis. Materials and methods: A total 27 US $II^{(R)}$ (Osstem, Korea) implants were placed in the mandibular edentulous area of 3 beagle dogs. The implant site was prepared by the conventional technique with drills, and three experimental groups were divided into under-drilling group, normal-drilling group and over-drilling group. The Implant Stability Quotient (ISQ) was measured at intervals of immediately, 4, 8, 12 weeks after placement using $Osstell^{(R)}$ mentor RFA. After the animals were sacrificed, histomorphometric evaluation was executed for measuring BIC and BD. Results: 1) The under-drilled group showed most high ISQ value for whole experiment period. 2) Bone-to-implant-contact(BIC) showed the tendency to be increased gradually as the experiment period passed except the 8 weeks of the normal group. 3) The under-drilled group showed most high bone density(BD) level for whole experiment period, and it was expressed the aspect to be increased gradually according to an experiment period passage in the average of all group. 4) Resonance frequency analysis and histomorphometric analysis are presumed by generally proportional. Conclusions: As this research result, it seems that there are some correlation between resonance frequency analysis and histomorphometric analysis. As are accomplished osseointegration stably so that more superior at the region which the overpressure comes to add, it will be applicable method in clinical field.

• 한국소음진동공학회논문집
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• 제20권11호
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• pp.995-1000
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• 2010

With the development of the auto industry, the automobile manufacturers demand to shorten development period and reduce the cost. Compared with the traditional method, applying the virtual prototype is more economical. This paper presents a method for parameters sensitivity analysis and optimizing the performance of vehicle noise and vibration. The existing design processes were repeatedly analyzed with a focus on vehicle performance to decide the design parameters of dimension, thickness, mounting type of body and chassis systems in the vehicle development period. This paper describes the prediction technique of vehicle performance using L18 orthogonal array layout, quality deviation analysis and parameter sensitivity analysis for robust design. This paper analyzed the performance correlation equation through the frequency and sensitivity database according to a design factor change. The new concept is that the performance prediction is possible without repeated activities of test and analysis. This paper described the parameter analysis applications such as bush dynamic stiffness and bush void direction of rear suspension. Design engineer could efficiently decide the design variable using parameter analysis database in early design stage. These improvements can reduce man hour and test development period as well as to achieve stable NVH performance.

• Advances in pediatric surgery
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• 제12권2호
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• pp.137-146
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• 2006

Pediatric surgery could establish a definitive position in the medical field on the basis of a stable patient population. Neonatal surgery, the core of pediatric surgery, requires highly skilled surgeons. However, recent advancement of prenatal diagnosis followed by intervention and decreased birth rate has resulted in a significant decrease in the neonatal surgical population and the number of surgical operations. The purpose of this study is to examine the outcome of neonatal surgeries and to propose a guide for the future surgeries. A total of 359 neonatal surgical patients operated upon at the Department of Surgery, Ewha Medical Center, during past 21 years were studied. The study period hasbeen divided into two time periods: from 1983 to 1993 and from 1994 to 2004. Analysis was based on the Clinical Classification System and mortality pattern, frequency of disorders, occurrence and cause of death, and other changes. Neonatal surgery was 6.4 % of all pediatric surgery during the total 21 year period, 9.9 % in the first period and 4.8 % in the second. Male to female ratio increased from 2.7:1 to 2.1:1. The overall mortality was 6.7 %, and there was significant decrease from 7.4 % in the first period to 6.0 % in the second. The clinical classification system (CCS) for death cases included class II 2, III 4, and IV 7 during the first period and class III 3, and IV 8 during the second, respectively. According to the mortality pattern by Hazebroek, there were 6 preventable death cases during the first period, and only one in the second, and 2 non-preventable death cases during the first period and 8 in second, respectively. Although the patients in the second period had more serious diseases, surgical mortality has been decreased in the second period, which may be the result of improved surgery methods for newborns and advanced patient care.

• Osong Public Health and Research Perspectives
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• 제5권4호
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• pp.187-192
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• 2014

Objectives: Measurement of the incidence of the human immunodeficiency virus (HIV) is very important for epidemiological studies. Here, we determined the recency period with the AxSYM avidity assay and the BED-capture enzyme immunoassay (BED-CEIA) in Korean seroconverters. Methods: Two hundred longitudinal specimens from 81 seroconverters with incident HIV infections that had been collected at the Korea National Institute of Health were subjected to the AxSYM avidity assay (cutoff = 0.8) and BED-CEIA (cutoff = 0.8). The statistical method used to estimate the recency period in recent HIV infections was nonparametric survival analyses. Sensitivity and specificity were calculated for 10-day increments from 120 days to 230 days to determine the recency period. Results: The mean recency period of the avidity assay and BED-CEIA using a survival method was 158 days [95% confidence interval (CI), 135-181 days] and 189 days (95% CI, 170-208 days), respectively. Based on the use of sensitivity and specificity, the mean recency period for the avidity assay and BED-CEIA was 150 days and 200 days, respectively. Conclusion: We determined the recency period to estimate HIV incidence in Korea. These data showed that the nonparametric survival analysis often led to shorter recency periods than analysis of sensitivity and specificity as a new method. These findings suggest that more data from seroconverters and other methodologies are needed to determine the recency period for estimating HIV incidence.

• 한국경영과학회지
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• 제31권1호
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• pp.83-90
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• 2006

By defining the partial busy period of the M/M/c/K queueing system as the time interval during which at least one server is in service, we derive the first two moments of both the partial busy period and the number of customers served during it. All expressions are given in explicit forms.

• 아동학회지
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• 제21권2호
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• pp.67-81
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• 2000

This study explores the concept of children as perceived in the late Chosun period by analyzing there sets of paintings on the panel screen, the Baekdongjado (the paintings of one hundred children at play). Although these paintings originated in China, there were many differences between Chinese and Korean paintings. Results of the analysis show that children were recognized as important members of the family by the late Chosun period, that parents hoped for many children, possibly sons, to fulfill each family, and that childhood meant the period of the youngster.

• 대한수학회지
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• 제61권4호
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• pp.693-711
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• 2024

A Markov-modulated Bernoulli process is a generalization of a Bernoulli process in which the success probability evolves over time according to a Markov chain. It has been widely applied in various disciplines for modeling and analysis of systems in random environments. This paper focuses on providing analytical characterizations of the Markovmodulated Bernoulli process by introducing key metrics, including success period, failure period, and cycle. We derive expressions for the distributions and the moments of these metrics in terms of the model parameters.

• 가정과삶의질연구
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• 제20권3호
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• pp.87-99
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• 2002

This is a study of discourses on the family used during the Enlightenment period in Korea. To this end, 1 have conducted a qualitative analysis of the editorials taken from the Taehan Maeil Sinbo of that period. The major findings are as follows: First, these Enlightenment period discourses claimed that civilized nations evolved from a family in primitive society. This concept of family is different from the concept of family in a Confucian society. Civilized societies believed the family is less important than the nation. At that time, Korean Press used the term bumoguk (Parental nation) to refer to the nation in an attempt to equate national loyalty to filial piety. Second, the Enlightenment period claimed that the nation belonged in the Public sphere while the family belonged in the private sphere. However, it was stated that it was the duty of the family to discipline the members and make them into good citizens. Finally, Enlightenment discourses used familyism as the basis of their arguments.

• Journal of Advanced Marine Engineering and Technology
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• 제30권1호
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• pp.134-139
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• 2006

A energy efficiency of quadruped walking robot has been studied mathematical modeling, dynamic analysis or simulation by consumption energy per period. In this paper, We used the quadruped walking robot Titan-VIII in order to carry out this experiment. The total moving length is about 2[m] , the stride length is 0.1, 0.2. 0.3, and walking period is changed by 1.0, 1.5, 2.0, 2.5 3.0[sec] Per each stride length. So consumption energy of 15 cases are measured. As a result of this experiment we obtained the best energy efficiency when stride length was 0.3[m], and Period was 1.5[sec].

• Communications for Statistical Applications and Methods
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• 제18권3호
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• pp.277-286
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• 2011

Global companies can sell their products with dierent warranty periods based on location and times. Customers can select the length of warranty on their own if they pay an additional fee. In this paper, we consider the warranty period and the repair time limit as random variables. A two-dimensional warranty policy is considered with repair times and failure times. The repair times are considered within the repair time limit and the failure times are considered within the warranty period. Under the non-renewable warranty policy, we obtain the expected number of warranty services and their variances in the censored area by warranty period and repair time limit to conduct a warranty cost analysis. Numerical examples are discussed to demonstrate the applicability of the methodologies and results using field data based on the proposed approach in the paper.