• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회 논문집
• /
• pp.1-8
• /
• 2005

Baiyangdian Lake, the largest freshwater lake in North China, is known as 'Pearl of North China' and 'kidney of North China' fur its abundant products and multiple ecological services. However, from the 1970s, due to the ever-increasing discharge of polluted water from upstream rivers, it has been severely polluted. Sediment Investigation and analysis were conducted on contents of heavy metal (Cu, Zn, Cd and Pb) from Baiyangdian Lake in June 2004. Results showed that pollution situation at downriver regions are more serious than that of upstream regions. The seriously polluted spots are access of Fuhe River, original wastewater reservoir of Tanghe River, densely populated Chunshui Village and Wangjiazhai Village. By using method of the potential ecological risk assessment, the heavy metal evaluation of polluted sediment has been conducted. The results showed that the contents of Cd and Pb were very high in sediment of Baiyangdian Lake. There were extremely stronger ecological risk for Cd and slight- medium ecological risk for Pd. According to the current situation of Baiyangdian Lake, countermeasures and suggestions have been put forward.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권9호
• /
• pp.105-115
• /
• 2020

The study empirically examines the effects of loan portfolio diversification on bank risk and return in the nascent banking market of Vietnam. Loan portfolio diversification is captured through the Hirschman-Herfindahl index and the Shannon Entropy with sectoral exposures. We access each bank's financial reports to collect the required data, especially the breakdown of sectoral loan portfolios, thus constituting a unique dataset. To compute bank return, we use the traditional accounting indicators, including return-on-assets, return-on-equity, and net-interest margin. For bank risk, we utilize the loan-loss provisions and non-performing loans relative to gross customer loans. Using a sample of 30 commercial banks over the period from 2008 to 2019 and the system generalized method of moments estimator for the dynamic panel, we indicate the downsides of portfolio diversification. Concretely, we observe that all diversification measures exhibit significantly negative signs in all regressions across different bank return proxies. At the same time, the estimates display the significant and positive impact of diversification on the non-performing loan ratio. Hence, sectoral loan portfolio diversification significantly hampers bank performance in both aspects of lower return and higher credit risk. The results are robust across a rich set of bank performance and portfolio diversification measures.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2020년도 가을 학술논문 발표대회
• /
• pp.69-70
• /
• 2020

Accidents in the construction industry are very high compared to other industries, and the number is also increasing steeply every year. Relevant studies were limited for solving the problems. The purpose of this study is to develop a comprehensive risk prediction process for personnel deployed at construction sites on safety management. First of all, the variables were divided into fixed, real-time and working types variables, and the relevant comprehensive data were collected. Second, the probability of a disaster was derived based on the collected data, and weights for each variable were calculated using the dummy regression analysis method using statistical methodology. Lastly, the resulting weighting and disaster probability equation was constructed, and The Final Risk Calculation Formula was developed. The Final Risk Calculation Formula presented in this study is expected to have a significant impact on the establishment of effective safety management measures to prevent possible safety accidents at construction sites

• 해양환경안전학회지
• /
• 제30권3호
• /
• pp.263-274
• /
• 2024

The digitization of ship environments has increased the risk of cyberattacks on ships. The smartization and automation of ships are also likely to result in cyber threats. The International Maritime Organization (IMO) has discussed the establishment of regulations at the autonomous level and has revised existing agreements by dividing autonomous ships into four stages, where stages 1 and 2 are for sailors who are boarding ships while stages 3 and 4 are for those not boarding ships. In this study, the level of a smart ship was classified into LEVELs (LVs) 1 to 3 based on the autonomous levels specified by the IMO. Furthermore, a risk assessment for smart ships at various LVs in different risk scenarios was conducted The cyber threats and vulnerabilities of smart ships were analyzed by dividing them into administrative, physical, and technical security; and mitigation measures for each security area were derived. A total of 22 cyber threats were identified for the cyber asset (target system). We inferred that the higher the level of a smart ship, the greater the hyper connectivity and the remote access to operational technology systems; consequently, the greater the attack surface. Therefore, it is necessary to apply mitigation measures using technical security controls in environments with high-level smart ships.

• Journal of Information Technology Applications and Management
• /
• 제18권1호
• /
• pp.55-74
• /
• 2011

The growth in the use of ubiquitous computing based on mobile services as an enabler to conduct business more effectively has been phenomenal. Technology acceptance model (TAM) has been applied in different contexts to examine a wide range of information technologies (IT). As more and more companies are finding ways to utilize ubiquitous computing based on mobile services, an important issue is to understand what factors will impact the decisions of consumers in adopting the services. Based on TAM with three additional groups of external factors, i.e., service-related factors (ubiquitous access, context awareness) and technology-related factors (perceived security risk, network connectivity) that are theoretically justified as having influence on both perceived usefulness and perceived ease of use which are additionally considered, a research model for the investigated technology acceptance was developed and empirically examined, using responses from more than intended users of ubiquitous computing based on mobile services. The specific purposes of this study are as follows. Firstly, this study is to identify service beliefs considering unique characteristics for ubiquitous services such as perceived ubiquitous access and perceived context awareness. Secondly, this study is to investigate network characteristics beliefs such as perceived security and perceived connectivity. Thirdly, this paper investigates the relationship among variables such as ubiquitous characteristics, network characteristics, behavioral beliefs, and intention to use ubiquitous web services. This study uses a structural equation model to test the research model. The major results of this study are as follows. Firstly, ubiquitous access has a influence on perceived usefulness and perceived ease of use. Context awareness has an influence on perceived usefulness. Secondly, User familiarity has an influence on perceived usefulness and perceived ease of use, and intention to use. User innovativeness has an influence on perceived ease of use. Thirdly, perceived security risk has an influence on perceived usefulness and perceived ease of use. Network connectivity has an influence on perceived usefulness and perceived ease of use. Fourth, there exist differential effects among factors in structural model among information, transaction, and entertainment services.

• Journal of Chest Surgery
• /
• 제44권1호
• /
• pp.25-31
• /
• 2011

Background: Mature autogenous arteriovenous fistulas have better long term patency and require fewer secondary interventions compared to arteriovenous prosthetic graft. Our Study evaluated vascular patency rates and incidence of interventions in autogenous arteriovenous fistulas and grafts. Material and Methods: A total of 166 vascular access operations were performed in 153 patients between December 2002 and November 2009. Thirty seven caeses were excluded due to primary access failure and loss of follow-up. One group of 92 autogenous arterioveous fistulas and the other group of 37 arteriovenous prosthetic grafts were evaluated retrospectively. Primary and secondary patency rates were estimated using the Kaplan-Meier method. Results: The primary patency rate (84%, 67%, 51% vs. 51%, 22%, 9% at 1, 3, 5 year; p=0.0000) and secondary patency rate (96%, 88%, 68% vs. 88%, 65%, 16% at 1, 3, 5 year; p=0.0009) were better in autogenous fistula group than prosthetic graft group. Interventions to maintain secondary patency were required in 23% of the autogenous fistula group (average 0.06 procedures/patient/year) and 65% of prosthetic graft group (average 0.21 procedures/patient/year). So the autogenous fistula group had fewer intervention rate than prosthetic graft group (p=0.01) The risk factor of primary patency was diabetus combined with ischemic heart disease and the secondary patency's risk factor was age. Conclusion: Autogenous arteriovenous fistulas showed better performance compared to prosthetic grafts in terms of primary & secondary patency and incidence of interventions.

• 융합보안논문지
• /
• 제11권4호
• /
• pp.43-49
• /
• 2011

웹 기반 의료정보는 많은 편리성을 제공하지만 공개된 네트워크 환경에서 나타나는 보안 취약성을 해결하지 않은 채 정보노출의 위험속에 사용이 확대되고 있다. 웹 기반 의료정보 접근시 보안문제에 대한 안전한 방법론 강구없이 기술만 발전시키려한다면 또 다른 위협의 요소를 증가시키는 것이다. 따라서 웹에 기반한 정보활용 보안대책 으로서 웹 기반 의료정보 접근제어 보안 메커니즘 기반 설계가 필요하다. 본 논문은 소프트웨어 아키텍쳐 설계사상을 기반으로 하여 의료정보시스템 접근제어 보안 메커니즘 기반을 설계 하였다. 그 방법론은 새로운 설계절차를 도출하고 아키텍쳐를 설계하며 기능 메커니즘 알고리즘을 구성하는 것 이다. 이를위해서는 웹 기반 다중 환자 정보 접근제어를 위한 보안 아케텍쳐 인프라스트럭가 필요하다. 제안하는 소프트웨어아케텍쳐는 소프트웨어 프레임워크를 도출하고 기능 메커니즘을 구성하는 기반에 관한 구조도를 도출했다. 제안된 시스템를 활용하여 의료정보 어플리케이션을 설계할때 의료정보 사용자는 실시간으로 데이터를 검색하면서도 통합화된 접근제어알고리즘의 보장하에서 정보관리 안전성을 확보하는 시스템 설계가 가능하다.

• 한국인터넷방송통신학회논문지
• /
• 제19권5호
• /
• pp.33-38
• /
• 2019

본 논문에서는 유럽연합의 개인정보 보호 규제인 GDPR을 준수하는 새로운 블록체인 모델을 제안한다. 제안하는 모델은 블록체인 거래에 포함된 개인정보에 대한 접근을 권한에 따라 차등적으로 통제하여 불법적인 개인정보 처리를 방지하는 한편, 보유기간이 경과된 또는 임의의 합법적 삭제 요청을 받은 개인정보에 대하여 접근을 영구히 차단하여 잊혀질 권리을 보장한다. 제안 모델의 핵심 메카니즘은, 개인정보를 접근정책에 따라 속성기반암호화한 후 이를 조회자의 속성(소속, 직무 등)을 반영한 일회용 토큰으로 복호화하는 것이다. 주목할 점은, 기존 기술이 제3의 신뢰기관을 필요로 하였다면 제안 모델은 신뢰기관 없이 블록체인에서 선발된 다수의 노드들로 하여금 그 기능을 대체하도록 하여 신뢰기관 리스크를 개선하였고, 아울러 속성 갱신에 따른 키 관리 효율성을 극대화하고자 복호키를 일회용 토큰으로 생성하였다는 점이다. 우리는 제안 모델을 허가형 블록체인인 패브릭의 체인코드를 이용하여 시뮬레이션 하고, 보안성을 분석함으로써 타당성을 입증하였다.

• 한국컴퓨터정보학회논문지
• /
• 제28권11호
• /
• pp.73-80
• /
• 2023

본 논문은 클라우드 서비스 시장을 활성화하기 위해 중요 정보의 접근을 보호하는 기술을 제안하였다. 클라우드 서비스 시장의 여러가지 저해요소 중에 클라우드 시스템에 저장되는 중요한 대외비 및 개인정보가 유출될 수 있는 문제를 해결하기 위한 기술을 제안하였다. 클라우드 서비스 제공자와 일반 사용자가 클라우드 자원에 대한 접근을 통제하여 중요 정보를 보호 할 수 있도록 하였다. 시스템 관리자는 시스템의 유지 및 관리를 위해 슈퍼유저의 권한을 갖는다. 클라이언트 컴퓨팅 서비스는 외부의 클라우드 서비스 공급자가 관리하고 정보 또한 외부시스템에 저장된다. 이러한 환경으로부터 사내의 중요 정보를 보호하기 위해 클라우드 서비스 공급자를 포함한 모든 사용자가 인증을 받고 자원을 접근할 수 있도록 하였다. 제안한 접근통제 기술을 통해 클라우드 컴퓨팅 자원에 대한 기밀성과 신뢰성 서비스를 제공하여 클라우드 서비스 시장의 활성화를 기대한다.

• Toxicological Research
• /
• 제21권2호
• /
• pp.87-98
• /
• 2005

Human exposure to nano-sized particles (NSP) has increased over the last century with anthropogenic sources, and the rapid development of nanotechnology becomes an another source of such exposure. Information regarding the safety of nanotechnology and its product, nanoparticles, is urgently needed when assuming exposure through inhalation, oral intake, and penetration across skin is ever increasing as growing nanotechnology rapidly. The recent advancement of biokinetic studies with NSP and newer epidemiologic and toxicologic studies with ultrafine particles can be the basis for the nanotoxicology. Some concepts of nanotoxicology can be known from the results of these results. Specific small size of NSP, when inhaled, facilitates deposition by difusional mechanism in all regions of the respiratory tract and uptake into cells, ranscytosis across epithelial and endothelial cells into the blood and lymph circulation to reach target sites. Translocation along axons and dendrites of neuron makes an access to CNS and ganglia. These biokinetics are dependent on NSP surface chemistry. Risk assessments of NSP include appropriate and relevant doses/concentration selections, the increase effects in the organism and the benefits of possible desirable effects. An interdisciplinary team approach is desirable for nanotoxicology research and an appropriate risk assessment.