• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.8 no.3
• /
• pp.895-905
• /
• 2018

Public opinion polls have a strong influence on modern society as a means of examining the tendency of social groups on specific issues. As the influence of the polls increases, the problem of forgery and falsification of the results becomes an important issue. So, to guarantee the reliability of the results, our society needs novel mechanisms. As one of such mechanisms, the Ethereum blockchain is an environment for developing decentralized applications with the reliable blockchain technology. Ethereum decentralized applications can utilize smart contracts to provide services for users in transparent and reliable ways. In this paper, we propose a polling method that guarantees reliability using the blockchain technology, which is a distributed ledger technique that makes forgery or falsification actually impossible. The proposed method provides a robust verification function on the results of the associated polls for individual voters and verification organizations. Also, we present a distributed opinion polling application running on our private Ethereum blockchain network, showing the effectiveness of the proposed method.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2002.12a
• /
• pp.135-138
• /
• 2002

본 논문에서는 비최소위상 시스템으로 표현되는 화력발전소 드럼의 수위제어를 위한 퍼지 제어기를 제안한다. 제안된 방법은 T. Takagi와 M. Sugeno의 퍼지모델을 기반으로 수행된다. 그리고 기존의 PID 및 LQ 제어기법을 적용한 방식과 비교하여 제안된 방법의 개선된 특성을 시뮬레이션 결과로부터 검증하였다.

• Journal of KIISE:Databases
• /
• v.32 no.6
• /
• pp.628-640
• /
• 2005

The XML is well accepted in several different Web application areas. As soon as many users and applications work concurrently on the same collection of XML documents, isolating accesses and modifications of different transactions becomes an important issue. When an XML document correctly corresponds to the rules laid out in a DTD or XML schema, it is also said to be valid. The valid XML document's validity should be guaranteed after the document is updated. The validation method mentioned above, however, results in lower degree of concurrency. For getting higher degree of concurrency and minimizing the range of the XML document validity, a new validation method based on a specific locking method is required. In this paper we propose the sequence group validation method for minimizing the range of the XML document validity. We also propose the boundary locking method for isolating accesses and modifications of different transactions while supporting the valid XML document's validity. Finally, the results of some experiments show the validation and locking methods increase the degree of transaction concurrency.

• Journal of Internet Computing and Services
• /
• v.5 no.1
• /
• pp.51-57
• /
• 2004

Mobile Internet allows users to request critical information and receive swift responses at any places, but mobile users could suffer from unreliable and ill-timed services due to the characteristics of wireless media, One way that reduces possibility of the unsatisfactory services is data replication. Data Replica1ion, however, inevitably induces the overhead of maintaining replica consistency which requires more expensive synchronization mechanism. We propose a new replicated data management scheme in distributed mobile environment, In order to alleviate negative impact of synchronization message overhead in fault-prone mobile Internet environment, we devise a new replication control scheme called proxy quorum consensus (PQC), PQC minimizes the message overhead by coordinating quorum access activities by means of proxy mediated voting (PMV) which exploits reliable proxy hosts instead of unreliable mobile hosts in voting process, We also propose a simulation model to show the performance of PQC. Based on the results of the performance evaluation, we conclude that PQC scheme outperforms the traditional schemes.

• International Journal of Highway Engineering
• /
• v.10 no.3
• /
• pp.221-230
• /
• 2008

In Korea, Expressway and National Highway System has been continually managed by their own pavement management system. The pavement condition evaluation system has not been developed for the municipal roads except for Seoul city. Therefore, this study focuses on analyzing the characteristics of distress in major city's pavement and developing the pavement condition index for the municipal PMS. Panel rating and pavement condition survey for the selected pavement sections were conducted for developing pavement condition index. Municipal level pavement condition index(MPCI) was developed by statistical analysis. Also, a sensitivity analysis for each independent variable of the MPCI and comparison with other pavement condition indicies, such as SPI and HPCI, were performed.

• Journal of Korea Technology Innovation Society
• /
• v.21 no.4
• /
• pp.1345-1365
• /
• 2018

Following principal-agent relationship between government and funding agency effects on efficiency and management of project, this paper suppose that project management cost rate variable on outsourcing and administration of institution, applies multiple regression analysis and logit analysis by using factors that procurement status of institutional operating expenses and each subordinates scale (Budget, subject number) and method (Top-down/Bottom-up), not a total amount, for examining factors following project efficiency analysis and way of commission. The major variables which effect on efficiency of institution are management cost scale (0.36), institutional operating expenses ratio (-0.47), way of outsourcing, the factors that affect way of outsourcing are portion of project management cost (-38.5) and institutional operating expenses rate (-11.7). This means both legal and financial stability are necessary and it is avoidable moral hazard and adverse selection on principal-agent problem.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.5
• /
• pp.403-413
• /
• 2010

Transition location of boundary layers over airfoils is predicted by using PSE(Parabolized Stability Equations) and $e^N$-method. Growth rates of disturbances are obtained from the PSE analysis and the N-factor curves are calculated by integrating the growth rates. The computational code developed in the present study is validated by comparing the computed results with the well known data for the cases of flat plate boundary layers and airfoils. Predictions of transition location are made for the boundary layers over NACA0012, NLF(1)-0414F, and NLF(1)-0416 airfoil. Predicted transition locations are found to be in good agreement with the experimental data.

• Journal of KIISE:Information Networking
• /
• v.30 no.6
• /
• pp.714-719
• /
• 2003

A Mobile IPv6 services exposes its vulnerability when a mobile node is roaming the subnets belonging to the different domains. The AAA infrastructure is strongly recommended when the ISPs need to authenticate the mobile user comes from the different domains. In addition to the basic requirements for the AAA service, the authentication latency and AAA message overhead should be minimized for the continuity of the mobile service. This paper considers the roaming service with AAA infrastructure in Mobile IPv6 and proposes an authentication scheme using delegation to authenticate the mobile node with effective manner. The effectiveness of the proposed scheme is confirmed using the cost analysis. The result shows at least 50% of performance enhancement when the MN is roaming fast under the control of the delegation.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1364-1368
• /
• 2008

우리나라의 한강, 낙동강, 금강, 섬진강, 그리고 영산강 유역에는 하나 이상의 저수지가 포함되어 있어 유역통합관리를 위한 의사결정지원시스템에 있어 저수지 운영기술은 필수적인 항목 중 하나이다. 반면, 적정한 저수지 운영율이 확립되어 있지 않아 저수지 운영을 고려한 유역통합관리에 어려움이 있으며, 저수지 운영율을 통합관리시스템에 적용하기 위한 적용방법 또한 확립되어 있지 않은 형편이므로 이에 대한 방안이 필요하다. 본 연구에서는 실적자료를 이용하여 금강유역의 용담댐과 대청댐 운영율을 구하고 수문학적상태를 이용하여 운영율을 적용방법을 제안하였다. 운영율을 구하기 위하여 금강유역에서 25년간의 일단위 유량자료와 저수지 운영자료를 수집하였으며, 수집된 자료를 토대로 실제 운영에 기반한 운영율을 개발하였다. 기존에 개발 검증된 금강유역의 네트워크 시스템에 개발된 운영율을 적용하기 위하여 수문학적상태를 사용하며 그 결과를 조절점의 실측유량 및 실적저수위, SSDP 저수위, SSDP-CoMOM 저수위를 사용한 명시적인 저수지 운영결과와 비교함으로써 개발된 운영율의 적용성을 검토하였다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.6 no.1
• /
• pp.90-96
• /
• 2011

In this paper, we propose a new discrete logarithm problem(DLP) based on the class semigroups of imaginary quadratic non-maximal orders using the special character of non-invertible ideal and analysis its security. To do this, we first explain the mathematical background explicitly and prove some properties of Cls (O) which relate to constructing the DLP and guaranteeing the security. To test the security of the proposed DLP, we compare the class number of the maximal order with that of the non-maximal order and investigate the unique factorization problems of ideals between class groups of the maximal orders and class semigroups of non-maximal orders to ensure the security of the cryptosystem.