• Title/Summary/Keyword: Uncertain System

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An Analytical Study on the Behavior of Slab Structure Considering the Remodeling (리모델링 공사를 고려한 슬래브 구조물의 거동에 관한 해석적 연구)

  • Choi, Hoon;Joo, Hyung-Joong;Lee, Seung-Sik;Yoon, Soon-Jong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.2
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    • pp.106-112
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    • 2010
  • Due to the improvement and stabilization of the social environment, construction market in the urban region is under shrinking. According, researches to lengthen the service life of the existing building structures are under the way through the remodeling or maintenance of deteriorated structures other than the new constructions. Similar situations are widely discussed in the domestic building construction market and the social importance of the remodeling of the existing building structures is increased. Although the structural stability of the building is uncertain due to the frequent repairing and structural changing, the remodeling works are usually conducted. In general, documents such as drawings and calculations for the design of the deteriorated structure to be remodeled are not kept. Accident at the remodeling site frequently occur because of the lack of thorough understanding of changed situations such as loadings, loading paths, changing of the mechanical properties of material, etc. In this paper, using the finite element analysis method, we investigated the structural behaviors of slab in the remodeling building and the results are applied to remodeling construction, and the appropriateness of the remodeling works are evaluated.

A Sanitary Survey on the Medicinal Water Springs Located near Taegu City(1986) (대구시 인근에 산재한 약수에 대한 위생학적 조사(1986))

  • Cha, Sang-Duk;Chang, Bong-Ki;Chun, Byung-Yeol;Kim, Doo-Hie
    • Journal of Preventive Medicine and Public Health
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    • v.19 no.2 s.20
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    • pp.273-280
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    • 1986
  • 'Medicinal water' have been used for the treatment of disease and the promotion of health. To study the quality and health effect of 'medicinal water', the eleven springs located near Taegu City during the period of March 27-February 17, 1986 were tested for biological and physiochemical examination and were checked for sanitary environment around the spring. Among them three springs (27.3%) had a good sanitary equipments and only one was negative for biological examination. Three 'medicinal warer' were accepted as potable by physicochemical examination. According to above findings, all of the 'medicinal water' sampled from the springs located near Taegu City were not potable by this sanitary survey adopted Drinking Water Standard in Korea. Kachang and Youngchum 'medicinal water' were more contaminated by heavy metals and bacteria than those of other springs. To solve the problem of contamination by heavy metals that originated from uncertain sources, we should search for the sources of water contamination, remove it completely and also support the environmental equipments and management system in protection of safe 'medicinal water' supply.

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A study on the effect of sensemaking of the chief executives of the social welfare organizations on their leadership development - Centered on the Community Care Centers for the Disabled - (사회복지기관장의 센스메이킹이 리더십 발현에 미치는 영향에 관한 연구 - 장애인복지관을 중심으로-)

  • Lee, Eun Kyung
    • Korean Journal of Social Welfare Studies
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    • v.44 no.3
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    • pp.207-236
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    • 2013
  • This article aims to understand the process of effective leadership in the Community Care Centers for the Disabled(CCCD). Using a qualitative approach and the concept of 'Sensemaking', a term introduced by Weick (1995), I described and explored the process of leadership. Sensemaking enables leaders to have a better grasp of what is going on in their environments. Sensemaking theory offers a perspective on leadership that resolves successfully complex situations surrounding the CCCD. The CCCDs face the environmental changes such as a paradigm shift of disability and a rivalry system with private services. In this time of uncertain change, the CCCDs are in need of leadership of the executives who could reduce complexity with shared meaning. Data were collected over 5 weeks from the 6 CCCDs, through semi-structured interviews, with practitioners, middle managers and chief executives. The interview scripts were thematically analyzed through Atlas-ti programme. The findings showed three subjects, the people's perception of environment, organizational visioning and interactions among post positions. Even though the 6 CCCDs were under the same environment, the perceptions and the enactments of the practitioners were influenced by the chief executives' sensemaking. The important factors of the chief executives' sensemaking were the daily interaction as well as ongoing reflection on their experiences.

Constraints and opportunities to sustain future wheat yield and water productivity in semi-arid environment

  • Ahmad, Mirza Junaid;Choi, Kyung-Sook
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.185-185
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    • 2019
  • Sustaining future wheat production is challenged by anthropogenically forced climate warming and drying led by increased concentration of greenhouse gases all around the globe. Warming stresses, originating from the elevated $CO_2$ concentration, are continuously reported to have negative impacts on wheat growth and yield. Yet, elevated $CO_2$ concentration, despite being disparagingly blamed for promoting warming, is also associated with a phenomenon called $CO_2$ enrichment; in which wheat yield can improve due to the enhanced photosynthesis rates and less water loss through transpiration. The conflicting nature of climate warming and $CO_2$ enrichment and their interplay can have specific implications under different environments. It is established form the field and simulation studies that the two contrasting phenomena would act severely in their own respect under arid and semi-arid environments. Wheat is a dietary staple for masses in Pakistan. The country's wheat production system is under constant stress to produce more from irrigated agricultural lands, primarily lying under arid to semi-arid environments, to meet the rapidly growing domestic needs. This work comprehensively examines the warming impacts over wheat yield and water productivity (WP), with and without the inclusion of $CO_2$ enrichment, under semi-arid environment of Punjab which is the largest agricultural province of Pakistan. Future wheat yields and WPs were simulated by FAO developed AquaCrop model v 5.0. The model was run using the bias-correction climate change projections up to 2080 under two representative concentration pathways (RCP) scenarios: 4.5 and 8.5. Wheat yield and WPs decreased without considering the $CO_2$ enrichment effects owing to the elevated irrigation demands and accelerated evapotranspiration rates. The results suggested that $CO_2$ enrichment could help maintain the current yield and WPs levels during the 2030s (2021-2050); however, it might not withhold the negative climate warming impacts during the 2060s (2051-2080). Furthermore, 10 - 20 day backward shift in sowing dates could also help ease the constraints imposed by climate warming over wheat yields and WPs. Although, $CO_2$ enrichment showed promises to counteract the adverse climate warming impacts but the interactions between climate warming and $CO_2$ concentrations were quite uncertain and required further examination.

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Development of Computer Code for Simulation of Multicomponent Aerosol Dynamics -Uncertainty and Sensitivity Analysis- (다성분 에어로졸계의 동특성 묘사를 위한 전산 코드의 개발 -불확실성 및 민감도 해석-)

  • Na, Jang-Hwan;Lee, Byong-Whi
    • Nuclear Engineering and Technology
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    • v.19 no.2
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    • pp.85-98
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    • 1987
  • To analyze the aerosol dynamics in severe accidents of LMFBR, a new computer code entitled MCAD (Multicomponent Aerosol Dynamics) has been developed. The code can treat two component aerosol system using relative collision probability of each particles as sequences of accident scenarios. Coagulation and removal mechanisms incorporating Brownian diffusion and gravitational sedimentation are included in this model. In order to see the effect of particle geometry, the code makes use of the concept of density correction factor and shape factors. The code is verified using the experimental result of NSPP-300 series and compared to other code. At present, it fits the result of experiment well and agrees to the existing code. The input variables included are very uncertain. Hence, it requires uncertainty and sensitivity analysis as a supplement to code development. In this analysis, 14 variables are selected to analyze. The input variables are compounded by experimental design method and Latin hypercube sampling. Their results are applied to Response surface method to see the degree of regression. The stepwise regression method gives an insight to which variables are significant as time elapse and their reasonable ranges. Using Monte Carlo Method to the regression model of LHS, the confidence level of the results of MCAD and their variables is improved.

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A Systematic Review and Meta-Analysis of Herbal Medicine for Frozen Shoulder (동결견의 한약 치료에 대한 체계적 문헌고찰 및 메타분석)

  • Oh, Tae-Young;Kim, Yeon-Hee;Oh, Eun-Mi;Hong, Su-Min;Ha, Hyun-Ju;Lee, Eun-Jung;Oh, Min-Seok
    • Journal of Korean Medicine Rehabilitation
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    • v.29 no.3
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    • pp.15-33
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    • 2019
  • Objectives The objective of this study is to provide the evidence of the effectivness of herbal medicine for frozen shoulder. Methods 2 Korean medical on-line databases (Oriental Medicine Advanced Searching Integrated System, Korean Traditional Knowledge), and 3 foreign databases (Pubmed, Cochrane library, China National Knowledge Infrastructure) were searched to find articles concerning herbal medicine for frozen shoulder. We selected randomized controlled trials (RCTs). Several repeated articles and those not relevant to the topic were excluded, as well as review articles and commentaries. The methodological quality of RCTs were evaluated using the Cochrane risk of bias tool and meta-analyes were perfomed. Results Total 474 studies were founded and 22 RCTs were selected for systematic review. Efficiency rate was used as the primary evaluation method. Almost studies reported that herbal medicine has significant effect on pain reduction, increasing shoulder function on frozen shoulder. 3 studies comparing herbal medicine and chuna with chuna and 3 studies comparing herbal medicine with ibuprofen were included in the meta-analysis. At herbal medicine and chuna with chuna meta-analysis, it showed positive results of herbal medicine for efficiency rate (risk ratio: 1.18, 95% confidence interval: 1.09-1.27, p<0.0001). At herbal medicine with ibuprofen medta-analysis, it showed positive results of herbal medicine for efficiency rate (risk ratio: 1.15, 95% confidence interval: 1.05-1.27, p=0.003). Conclusions The studies showed that herbal medicine can significantly effective on frozen shoulder. However, the risk of bias in RCTs were evaluated as uncertain. In the future, further well-designed RCTs are needed to prove the effectiveness of herbal medicine for frozen shoulder and reduce the risk of bias.

Utility of Computed Tomography in a Differential Diagnosis for the Patients with an Initial Diagnosis of Chronic Obstructive Pulmonary Disease Exacerbation

  • Park, Hyung Jun;Kim, Soo Han;Kim, Ho-Cheol;Lee, Bo Young;Lee, Sei Won;Lee, Jae Seung;Lee, Sang-Do;Seo, Joon Beom;Oh, Yeon-Mok
    • Tuberculosis and Respiratory Diseases
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    • v.82 no.3
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    • pp.234-241
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    • 2019
  • Background: The utility of computed tomography (CT) in the differential diagnosis of patients with chronic obstructive pulmonary disease (COPD) exacerbation remains uncertain. However, due to the low cost associated with CT scan along with the impact of Koreas' health insurance system, there has been a rise in the number of CT scans in the patients with initial diagnosis of COPD exacerbations. Therefore, the utility of CT in the differential diagnosis was investigated to determine whether performing CT scans affect the clinical outcomes of the patients with an initial diagnosis of COPD exacerbation. Methods: This study involved 202 COPD patients hospitalized with an initial diagnosis of COPD exacerbation. We evaluated the change in diagnosis or treatment after performing a CT scan, and compared the clinical outcomes of patient groups with vs. without performing CT (non-CT group vs. CT group). Results: After performing CT, the diagnosis was changed for two (3.0%) while additional diagnoses were made for 27 of the 64 patients (42.1%). However, the treatment changed for only one (1.5%), and six patients (9.3%) received supplementary medication. There were no difference in the median length of hospital stay (8 [6-13] days vs. 8 [6-12] days, p=0.786) and intensive care unit care (14 [10.1%] vs. 11 [16.7%], p=0.236) between the CT and non-CT groups, respectively. These findings remained consistent even after the propensity score matching. Conclusion: Utility of CT in patients with acute COPD exacerbation might not be helpful; therefore, we do not recommend chest CT scan as a routine initial diagnostic tool.

A Study on the Algorithms for One-way Transmission in IPv6 Environment (IPv6 환경에서의 일방향 통신 알고리즘에 대한 연구)

  • Koh, Keun Ho;Ahn, Seong Jin
    • Convergence Security Journal
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    • v.17 no.5
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    • pp.63-69
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    • 2017
  • In the early 1990s, IETF(Internet Engineering TaskForce) had started the discussion on new address protocol that can modify and supplement various drawbacks of existing IPv4 address protocol with the introduction of CIDR(Classless Inter-Domain Routing) which is a temporary solution for IPv4 address depletion, NAT, private IP address. While various standards related to new address protocol has been proposed, the SIPP(Simple Internet Protocol Plus) was adopted among them because it is regarded as the most promising solution. And this protocol has been developed into current IPv6. The new concepts are introduced with modifying a lot of deficiencies in the exisitng IPv4 such as real-time data processing, performance on QoS, security and the efficiency of routing. Since many security threats in IPv6 environment still exist, the necessity of stable data communication environment has been brought up continuously. This paper deveopled one-way communication algorithm in IPv6 based on the high possibility of protecting the system from uncertain and potential risk factors if the data is transmitted in one way. After the analysis of existing IPv6 and ICMPv6, this paper suggests one-way communication algorithm as a solution for existing IPv6 and ICMPv6 environment.

Judgement of Violation of the Protection Duty of Internet Service Provider (인터넷 서비스 제공자의 보호조치 의무 위반의 판단)

  • Kang, Juyoung;Kim, Hyunji;Lee, Hwansoo
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.6 no.7
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    • pp.17-26
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    • 2016
  • Information spill was occurred several times in the country due to the negligence of the large internet service providers including SK Communications, Auction, KT. In order to judge the Internet Service Provider(ISP)'s liability in individual data spill caused by hacking, the violation of existing legislation or general principle of law's good faith principle has to be examined. However, based on current ISP's good faith principle, there is no objective standard for judging liability. Such uncertain range of protection action duty based on good faith principle generates complaint toward companies, therefore presentation of objective judgement range index on how to determine this range is needed. However due to the legal characteristic of above-mentioned law, it is not possible to fix the range of protection action duty and regulate it on law. In order to resolve this, rather than concerning simply on legal system level, fusion approach method is needed. Thus, this research will discuss the measure for objective standard for predicting ISP's range of protection action duty through fusion view dividing in technical, legal and administrative aspects.

A Study on Efficient AI Model Drift Detection Methods for MLOps (MLOps를 위한 효율적인 AI 모델 드리프트 탐지방안 연구)

  • Ye-eun Lee;Tae-jin Lee
    • Journal of Internet Computing and Services
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    • v.24 no.5
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    • pp.17-27
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    • 2023
  • Today, as AI (Artificial Intelligence) technology develops and its practicality increases, it is widely used in various application fields in real life. At this time, the AI model is basically learned based on various statistical properties of the learning data and then distributed to the system, but unexpected changes in the data in a rapidly changing data situation cause a decrease in the model's performance. In particular, as it becomes important to find drift signals of deployed models in order to respond to new and unknown attacks that are constantly created in the security field, the need for lifecycle management of the entire model is gradually emerging. In general, it can be detected through performance changes in the model's accuracy and error rate (loss), but there are limitations in the usage environment in that an actual label for the model prediction result is required, and the detection of the point where the actual drift occurs is uncertain. there is. This is because the model's error rate is greatly influenced by various external environmental factors, model selection and parameter settings, and new input data, so it is necessary to precisely determine when actual drift in the data occurs based only on the corresponding value. There are limits to this. Therefore, this paper proposes a method to detect when actual drift occurs through an Anomaly analysis technique based on XAI (eXplainable Artificial Intelligence). As a result of testing a classification model that detects DGA (Domain Generation Algorithm), anomaly scores were extracted through the SHAP(Shapley Additive exPlanations) Value of the data after distribution, and as a result, it was confirmed that efficient drift point detection was possible.