• Tuberculosis and Respiratory Diseases
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• v.52 no.1
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• pp.37-45
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• 2002

Background: Diffuse panbronchiolitis(DPB) is a chronic inflammatory lung disease that presents as coughing, copious sputum, exertional dyspnea, which progresses to bronchiectasis. The pathogenesis of bronchiectasis is controlled by inflammatory mediators, which are closely related to mucus hypersecretion, goblet cell dysplasia. In recent studies, the epidermal growth factor receptor(EGFR) system was reported to be associated with this process. It was hypothesized that a relationship exists between goblet cell dysplasia, EGFR expression, and inflammatory mediators produced by neutrophil. Method: Alcian blue/periodic acid -Schiff(AB/PAS) stain, MUC5AC, EGFR, CD16 immunohistochemical stain were examined to investigate a role for the EGFR system in a mucus hypersecretion in DPB using the lung biopsy specimens from 13 DPB patients and 6 controls. Results : In the DPB group, the AB/PAS and MUC5AC -stained areas were $8.31{\pm}3.36%$, $11.46{\pm}4.68%$, respectively. In the control group, the AB/PAS- and MUC5AC-stained areas were $50.5{\pm}5.77%$, $53.3%{\pm}6.67%$, which was significantly larger than in the DPB group (each comparison, p<0.05). The percentage of EGFR expression was $9.54{\pm}4.95%$ in the DPB group, but zero in of the control group. The extent of neutrophilic infiltration was $71.92{\pm}3.71$/5HPF in the DPB group and $45.0{\pm}5.73$/5HPF in the control group, which was statistically significant(p=0.002). Conclusion: The EGFR system is highly related to goblet cell dysplasia, mucus hypersecretion and neutrophilic inflammation in DPB.

• Journal of KIISE:Databases
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• v.28 no.4
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• pp.742-757
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• 2001

Since database management systems(DBMSS) have limited lock resources, transactions requesting locks beyond the limit mutt be aborted. In the worst carte, if such transactions are aborted repeatedly, the DBMS can become paralyzed, i.e., transaction execute but cannot commit. Lock escalation is considered a solution to this problem. However, existing lock escalation methods do not provide a complete solution. In this paper, we prognose a new lock escalation method, adaptive lock escalation, that selves most of the problems. First, we propose a general model for lock escalation and present the concept of the unescalatable look, which is the major cause making the transactions to abort. Second, we propose the notions of semi lock escalation, lock blocking, and selective relief as the mechanisms to control the number of unescalatable locks. We then propose the adaptive lock escalation method using these notions. Adaptive lock escalation reduces needless aborts and guarantees that the DBMS is not paralyzed under excessive lock requests. It also allows graceful degradation of performance under those circumstances. Third, through extensive simulation, we show that adaptive lock escalation outperforms existing lock escalation methods. The results show that, compared to the existing methods, adaptive lock escalation reduces the number of aborts and the average response time, and increases the throughput to a great extent. Especially, it is shown that the number of concurrent transactions can be increased more than 16 ~256 fold. The contribution of this paper is significant in that it has formally analysed the role of lock escalation in lock resource management and identified the detailed underlying mechanisms. Existing lock escalation methods rely on users or system administrator to handle the problems of excessive lock requests. In contrast, adaptive lock escalation releases the users of this responsibility by providing graceful degradation and preventing system paralysis through automatic control of unescalatable locks Thus adaptive lock escalation can contribute to developing self-tuning: DBMSS that draw a lot of attention these days.

• Journal of Life Science
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• v.33 no.2
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• pp.169-175
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• 2023

As a protective defensive mechanism against ultraviolet (UV) light exposure in skin tissue, melanocytes produce the pigment melanin. Tyrosinase plays a key role in melanin production in melanocytes. However, the overproduction of melanin can lead to lesions, such as freckles and dark spots. Thus, it is clinically important to find a modulating molecule to control melanogenesis by regulating tyrosinase expression and/or activity. It is known that catechin, a plant flavonoid, can reduce melano- genesis through the downregulation of tyrosinase expression. Here, we tested whether catechin derivatives isolated from the stem bark of Ulmus parvifolia have an effect on melanin production by regulating tyrosinase in mouse melanoma cells and in vitro mushroom tyrosinase. The catechin derivatives used in this study included C5A, C7A, C7G, and C7X. Treatments using these catechin derivatives reduced melanin production in mouse melanoma B16F10 cells in which melanogenesis was stimulated by α-MSH. Notably, the anti-melanogenic effects of catechin derivatives were similar to those of kojic acid, a well-known anti-melanogenic molecule. Both C5A and C7A directly inhibited the activity of tyrosinase isolated from mushrooms in vitro. Furthermore, our in silico computational simulation showed that these two compounds were expected to bind to the active site of tyrosinase, which is similar to kojic acid. In addition, all four catechin derivatives reduced tyrosinase protein expression. In summary, our results showed that catechin derivatives can reduce melanogenesis by regulating tyrosinase activity or expression. Thus, this study suggests that catechin derivatives isolated from U. parvifolia can be novel modulators of melanin production.

• The KIPS Transactions:PartC
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• v.10C no.3
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• pp.355-366
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• 2003

Today's market share of mobile internet service is growing rapidly in internet due to the rapid advances in wireless mobile networks. To guarantee for QoS of Mobile Nodes in wireless mobile networks, we propose the Proxy MRSVP (PMRSVP) which is efficient resource reservation protocol. The PMRSVP using a modified regional registration restrains excessive message generation from existing protocols that propose an alternative plan of existing best effort service in wireless mobile networks. We show that signaling message generation quantities and resource registration costs of the PMRSVP are lower than MRSVP and Hierarchical MRSVP (HMRSVP) because as Mobile Agent (MA) plays a proxy role instead of Corresponding Host (CH). We evaluate resource reservation cost with registration cost of intradomain and interdomain of the proposed method in the paper by comparing to that of the MRSVP and HMRSVP.

• Journal of Korean Academy of Nursing
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• v.25 no.4
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• pp.790-806
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• 1995

The present study examined the causal relationships among nurses' job environment /job characteristics(work overload, lack of autonomy, professional role conflict, interpersonal relationships), maturity, job stress, job satisfaction and turnover intention by constructing and testing a theoretial framework. Based on Katz and Kahn's (1978) theory of organizational open system and Kahn, Wolfe, Quinn, and Snoek's (1964) theory of stress, nurses' turnover intention, job satisfaction and job stress were conceived of as outcomes of the interplay between personal characteristics and work environment. Personal aspects associated with outcome variables included professional knowlege and skill, and maturity(challenge, commitment, control, responsibility). The work environment factors involved work overload, lack of autonomy, professional role conflict, and interpersonal relationships (social support). Three university hospitals located in Seoul were selected to participate. The total sample of 443 registered nurses represents a response rate of 96 percent. Linear structural relationships (LISREL) technique was used to test the fit of the proposed conceptual model to the data and to examine the causal relationships among variables. The result showed that both the proposed model and the modified model fit the data excellently, revealing considerable explanatinal power for job stress and job satisfaction. The explanatory power of turnover intention was relatively lower than those of stress and satisfaction. In predicting nurses' stress, satisfaction and turnover intention, the findings of this study clearly demonstrated that professional role conflict might be the most important variable of the all the environmental variables and personal characteristics. The results were dis-cussed, including directions for the future research and practical implications drawn from the research were suggested.

• The Journal of the Korea Contents Association
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• v.17 no.4
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• pp.275-284
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• 2017

Modularity has merits in modifiability of product structure management and product arrangement. This feature helps consumer to expand the selection of products and to get customized products. Also consumers are drive satisfaction and reduce a post-purchase dissonance from role in a 'prosumer'. But expanding product's alternative would cause the overload confusion by rising complexity of information handling. Purpose of the study is to verify how interaction about option size and personal disposition are effected consumer's overload confusion. For this purpose we deducted 3 personal dispositions 'Regulatory focus', 'Product familiarity', 'Self-efficacy' that presented lead to potential effect of personal information handling by previous research. By statistical inquiry prevent focus group had perceived more overload confusion than promotion focus group in an expanding option size circumstances. And low Product familiarity and Self-efficacy group had perceived more overload confusion than high Product familiarity and Self-efficacy group in a expanding option size circumstances.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.373-380
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• 2020

A valve product can be over-designed or too heavy. Finite element analysis was performed using ANSYS for two and three-dimensional ball valve models, and the ball weight was reduced by optimization within the allowable design criteria. The ball is structurally safe according to the computed stress values, which are within the material's admissible stress. The weight was reduced by about 22%, and the structural safety factor was 1.25. The structural safety of the seat insert and ring, which are used to prevent leakage, was confirmed through finite element analysis. It is shown that the two-dimensional analysis can result in similar values to the three-dimensional analysis for the axisymmetric structure. The redesign of the valve is not included in the results since such changes require a whole new design process, including all valve components.

• Journal of The Korean Association For Science Education
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• v.15 no.4
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• pp.487-494
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• 1995

본 연구는 우리 나라의 성인들이 자신의 초중등 학교 시절 경험하였던 학교 과학교육에 대해 어떤 종류의 즐거운 혹은 괴로운 기억들을 현재까지 갖고 있는가를 탐색하였다. 성인들은 오래 전 경험하였던 매우 인상적인 활동이나 장면들을 통해 학교 과학교육을 기억할 것이고, 이러한 기억은 그들의 학교 과학교육에 대한 전반적인 태도에 결정적인 역할을 할 것이다. 따라서 성인들의 학교 과학교육에 대한 이러한 기억들을 살펴보면, 학교 과학교육의 특징을 이해하고 장기적으로 학교 과학교육을 보다 즐거운 경험의 장으로 만드는 데 도움이 될 것이다. 본 연구는 소규모의 설문 조사를 통해 이루어졌으며, 설문 대상은 대구지역의 30-50대 성인 88명이었다. 설문은 현재 과학과 관련된 특정한 직업을 갖고 있지 않은 사람을 대상으로 하였으며, 설문에서 응답자들은 자신들의 초중등 학교 과학교육을 받으면서 가장 즐거웠던 기억과 가장 괴로웠던 기억이 구체적으로 무엇이며 이러한 경험은 초중고 어느 때이었는가를 응답하였다. 성인들이 가장 즐거웠던 기억으로 지적한 것은 실험 실습 활동(65.9%), 야외학습 활동(19.3%) 등으로 전통적인 교실수업 이외의 활동이 약 86%로 나타났다. 그리고 효과적인 교실수업, 교사의 인성적 특징, 과학전람회 참가 등의 경험을 언급한 경우도 부분적으로 있었다. 성인들이 가장 괴로웠던 기억으로 지적한 것은 따분한 교실수업(51.1%), 실험 실습 활동의 부정적인 측면(28.4%) 등으로 나타났으며, 부분적으로 과다한 숙제, 교사의 인성적 특징, 야외학습 활동, 과학수업의 부재 등을 지적한 경우도 있었다. 또한 전체적으로 즐거웠던 기억은 국민학교 시절의 경험에서(56.8%), 반면 괴로웠던 기억은 고등학교 시절의 경험에서(44.3%) 많이 나타났다. 특히, "개구리 해부 실험" 의 경우, 7명이 가장 즐거웠던 기억으로 8명은 가장 괴로웠던 기억으로 언급하여 매우 상반된 견해를 나타냈다. 따라서 동일한 활동일지라도 학생들에게는 매우 상반된 경험으로 작용하게 되며, 이 경우 생명체에 대한 과학실험의 윤리적 문제와 이에 대한 갈등을 분명하게 드러냈다.

• Journal of Korea Port Economic Association
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• v.23 no.4
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• pp.115-137
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• 2007

Due to the economic growth of China and the geographic advantage that Gunsan and Janghang ports are close to China, recently traffic of China is rapidly increasing and the role of Gunsan & Janghang ports as a gateway port of west coast became more important. There, however, remains that Gunsan and Janghang port still don't equip with enough facilities and strategies to handle increasing traffic. The purpose of this paper is to analyze O/D data of Gunsan.Janghang Port and present the result of O/D as preliminary data. O/D data of Gunsan and Janghang had been analyzed by kinds of general cargoes and from/to China's ports and this paper suggests to the competitive strategies of Gunsan and Janghang port to attract cargoes from/to China particularly.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2000.09a
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• pp.93-103
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• 2000

The concrete plug in an underground cavern prevents the stored product (oil, gas, etc) from leaking and the excessive show of underground water, so it plays an important role in construction and operation of the storage cavern. Additionally, it should maintain its stability under every possible loading condition. Once the plug is constructed, the cavern is isolated from the external access. Therefore, mechanical and hydraulic consideration should be made in construction to fulfill its function. Therefore, in this study, numerical analyses were conducted to study the optimal shape and thickness of the plug with respect to the various conditions of installation depth, the shape of the plug, in-situ stress ratio (K), the condition of rock-plug interface, and the effect of Excavation Damaged Zone (EDZ). This paper also presents the effect of slot depth on the hydraulic behavior of the plug. These analyses were carried out by using the 2-dimensional finite difference code, rm FLAC, and the 3D code, m FLA $C^{3D}$./.