• 한국통신학회논문지
• /
• 제37B권11호
• /
• pp.965-974
• /
• 2012

최근 스마트 디바이스 사용이 대중화 되고 업무 환경 또한 PC중심에서 스마트 디바이스로 확대되어 가면서 무선트래픽 양이 급격하게 증가 되고 있다. Enterprise 네트워크 에서 무선 IP 대역과 무선 트래픽 대역폭 관리는 중요한 사항이 되고 있다. 네트워크 설계 시 단말 호스트들의 네트워크 접속 유형 판별은 효율적인 네트워크 설계와 관리에 큰 이점이 된다. 또한 판별된 단말 호스트의 지속적인 관리를 통해 효과적인 네트워크 운용이 가능하고, 접속 유형의 변화를 통해 NAT 사용 호스트를 판별 할 수 있다. 본 논문에서는 Enterprise 네트워크의 인터넷 접속점에서 수집된 트래픽의 RTT(Round-Trip-Time) 값을 이용하여 단말 호스트의 접속 유형을 판별하는 방법론을 제안한다. 또한, 실제 학내 망을 대상으로 제안하는 방법의 타당성을 증명한다.

• 한국공간구조학회논문집
• /
• 제20권4호
• /
• pp.141-147
• /
• 2020

Single-layered grid space steel roof structure is an architectural system in which the structural ability of the nodal connection system greatly influences the stability of the entire structure. Many bolt connection systems have been suggested to enhance for better construct ability, but the structural behavior and maximum resistance of the connection system according to the size of bolt clearance play were difficult to identify. In particular, the identification of bending stiffness of the connection system is very important due to the characteristics of shell structures in which membrane stresses based on bending force effect significantly. To identify effective structural behavior and maximum bearing force, four representative nodal connection systems were selected and nonlinear numerical analysis were performed. The numerical analysis considering the size of the bolt clearance were performed to investigate structural behavior and maximum values of the bending force. In addition, the type of effective nodal connection system were evaluated. As a result, the connection system, which has two shear plane, represented high bending stiffness.

• Steel and Composite Structures
• /
• 제10권6호
• /
• pp.541-561
• /
• 2010

This paper presents finite element analyses, experimental measurements and finite element model updating of an arch type steel laboratory bridge model using semi-rigid connections. The laboratory bridge model is a single span and fixed base structure with a length of 6.1 m and width of 1.1m. The height of the bridge column is 0.85 m and the maximum arch height is 0.95 m. Firstly, a finite element model of the bridge is created in SAP2000 program and analytical dynamic characteristics such as natural frequencies and mode shapes are determined. Then, experimental measurements using ambient vibration tests are performed and dynamic characteristics (natural frequencies, mode shapes and damping ratios) are obtained. Ambient vibration tests are performed under natural excitations such as wind and small impact effects. The Enhanced Frequency Domain Decomposition method in the frequency domain and the Stochastic Subspace Identification method in the time domain are used to extract the dynamic characteristics. Then the finite element model of the bridge is updated using linear elastic rotational springs in the supports and structural element connections to minimize the differences between analytically and experimentally estimated dynamic characteristics. At the end of the study, maximum differences in the natural frequencies are reduced on average from 47% to 2.6%. It is seen that there is a good agreement between analytical and experimental results after finite element model updating. Also, connection percentages of the all structural elements to joints are determined depending on the rotational spring stiffness.

• International Journal of Computer Science & Network Security
• /
• 제21권9호
• /
• pp.91-98
• /
• 2021

Peer to Peer Networks play an increasing role in today's networks, also it's expected that this type of communication networks evolves more in the future. Since the number of users that is involved in Peer to Peer Networks is huge and will be increased more in the future, security issues will appear and increase as well. Thus, providing a sustainable solution is needed to ensure the security of Peer to Peer Networks. This paper is presenting a new protocol called Malicious Trust Managers Identification (MTMI). This protocol is used to ensure anonymity of trust manager, that computes and stores the trust value for another peer. The proposed protocol builds a secure connection between trust managers by using public key infrastructure. As well as experimental testing has been conducted to validate the proposed protocol.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 D
• /
• pp.2633-2635
• /
• 2003

In this study, we propose a fuzzy polynomial neural networks (FPNN) and a genetically optimized fuzzy polynomial neural networks(GoFPNN) for identification of non-linear system. GoFPNN architecture is designed by a FPNN based on fuzzy set and its structure and parameters are optimized by genetic algorithms. A fuzzy neural networks(FNN) based on fuzzy set divide into two structures that is simplified inference structure and linear inference structure. The proposed FPNN is resulted from integration and extension of simplified and linear inference structure of FNN. The consequence structure of the FPNN consist of polynomials represented by networks using connection weights for rules. The networks comprehend simplified(Type 0), linear (Type 1), and quadratic(Type 3) inferences. The proposed FPNN can select polynomial type of consequence part for each rule. Therefore, proposed scheme can offer flexible structure design capability for a system characteristics. Moreover, GAs is applied to networks structure and parameters tuning of proposed FPNN, and its efficient application method is discussed, these subjects are result in GoFPNN that is optimal FPNN. To evaluate proposed model performance, a numerical experiment is carried out.

• 한국화재소방학회논문지
• /
• 제34권3호
• /
• pp.76-84
• /
• 2020

대부분의 콘센트 화재는 플러그 핀과 핀받이 주변에서 발생하는 것으로 알려져 있다. 하지만, 플러그 접속점 이외에 콘센트의 전원 접속구에서도 화재가 발생할 수 있다는 것을 간과하면 안 된다. 본 연구에서는, 전원 접속구에 연선이 불완전하게 접속될 때, 발화 가능성을 확인하였다. 실험은 기초실험과 재현실험으로 나누어 진행하였다. 기초실험은 접속구에 체결되는 연선의 가닥 수에 따른 발화 가능성을 확인하고 잔존물의 특징을 파악하였다. 재현실험은 전등, 청소기, 히터 등의 부하를 콘센트에 연결하고 접속구에서의 발화가 화재로 진전되는지 확인하였다. 실험 결과, 접속구에서 발생한 발열과 아크로 인해 화재로 진전되었고, 잔존물인 U-자 고정금구와 클립에서 부분적 손실이 식별되었다. 이에 따라, 연선을 사용한 전기배선이 콘센트에 불완전 접속되었을 때, 화재의 발생 가능성을 증명하였고, 잔존물의 특징으로부터 화재원인을 판정할 수 있다는 것을 확인하였다.

• 한국위험물학회지
• /
• 제2권1호
• /
• pp.31-37
• /
• 2014

Since the unprecedented hydrogen fluoride leak accident in 2012, there has been growing demand for customized technical information for rapid response and chemical accident management agencies including the Ministry of Environment, the National Emergency Management Agency, and the National Police Agency need more information on chemicals and accident management. In this regard, this study aims to provide reliable technical data and guidelines to initial response agencies, similar to accident management technical reports of the US and Canada. In this study, we conducted a questionnaire survey and interviews on initial response agencies like fire stations, police stations, and local governments to identify new information items for appropriate initial response and improvements of current guidelines. We also collected and reviewed the Canada's TIPS, US EPA's hydrogen fluoride documents, domestic and foreign literature on applicability tests of control chemicals, and interview data, and then produced items to be listed in the technical guidelines. In addition, to establish database of on-site technical information, we carried out applicability tests for accident control data including ① emergency shut down devide, safety guard, shut down valve, ground connection, dyke, transfer pipe, scrubber, and sensor; ② literature and field survey on distribution type and transportation/storage characteristics (container identification, valve, ground connection, etc.); ③ classification and identification of storage/transportation facilities and emergency management methodslike leak prevention, chemicals control, and cutoff or bypass of rain drainage; ④ domestic/foreign analysis methods and environmental standards including portable detection methods, test standards, and exposure limits; and ⑤ comparison/evaluation of neutralization efficiency of control chemicals on toxic substances.

• Computers and Concrete
• /
• 제15권5호
• /
• pp.771-794
• /
• 2015

This paper proposes an innovative method for selection of measurement sets in static parameter identification of concrete or steel bridges. This method is proved as a systematic tool to address the first steps of Structural System Identification procedures by observability techniques: the selection of adequate measurement sets. The observability trees show graphically how the unknown estimates are successively calculated throughout the recursive process of the observability analysis. The observability trees can be proved as an intuitive and powerful tool for measurement selection in beam bridges that can also be applied in complex structures, such as cable-stayed bridges. Nevertheless, in these structures, the strong link among structural parameters advises to assume a set of simplifications to increase the tree intuitiveness. In addition, a set of guidelines are provided to facilitate the representation of the observability trees in this kind of structures. These guidelines are applied in bridges of growing complexity to explain how the characteristics of the geometry of the structure (e.g. deck inclination, type of pylon-deck connection, or the existence of stay cables) affect the observability trees. The importance of the observability trees is justified by a statistical analysis of measurement sets randomly selected. This study shows that, in the analyzed structure, the probability of selecting an adequate measurement set with a minimum number of measurements at random is practically negligible. Furthermore, even bigger measurement sets might not provide adequate SSI of the unknown parameters. Finally, to show the potential of the observability trees, a large-scale concrete cable-stayed bridge is also analyzed. The comparison with the number of measurements required in the literature shows again the advantages of using the proposed method.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2003년도 추계학술발표논문집
• /
• pp.209-216
• /
• 2003

There are two kinds of controllers in a continuous process system. One is for tension control of a moving web and the other for lateral motion control. The inter-connection between tension and lateral behaivior of web has not yet been considered in the analysis of web dynamics and designing of control stragagies. But the effect of tension variation on the lateral motion of a moving web is observed in the most manufacturing systems. In this paper, experimental studies was carried out to find out the inter-correlation between tension and lateral motion of a web using a 3-span web transport system which consists of two displacement type guiders. As a result, it was found that there are typical operating conditions that tension and lateral motion are correlated each other.

• Archives of Plastic Surgery
• /
• 제38권6호
• /
• pp.836-844
• /
• 2011

Purpose: Hands are the chief organs for physically manipulating the environment, using anywhere from the roughest motor skills to the finest, and since the fingertips contain some of the densest areas of nerve endings on the human body, they are continuously used organ with complex functions, and therefore, often gets injured. To prevent any functional loss, a detailed anatomical knowledge is required to have a perfect surgical treatment. Also it is necessary to have a thorough understanding of arrangements of the human extensor tendons and intertendinous connections when tenoplasty or tendon transfer is required. We performed a study of the arrangements of the human extensor tendons and the configuration of the intertendinous connections over the dorsum of the wrist and hand. Methods: A total of 58 hands from Korean cadavers were dissected. The arrangements of extensor indicis proprius, extensor digitorum communis, and extensor digiti minimi tendons and intertendinous connections were studied. Results: The most common distribution patterns of the extensor tendons of the fingers were as follows: a single extensor indicis proprius (EIP) tendon which inserted ulnar to the extensor digitorum-index (EDC-index); a single EDC-index; a single EDC-middle; a double EDC-ring; an absent EDC-little; a double extensor digiti minimi (EDM), a single EDC-index (98.3%), a single EDC-middle (62%), a double EDC-ring (50%), and an absent (65.5%) or a single (32.8%) EDC-little. A double (70.6%) EDM tendons were seen. Intertendinous connections were classified into 3 types: type 1 with thin filamentous type, type 2 with a thick filamentous type, and type 3 with a tendinous type subdivided to r shaped 3r type and y shaped 3y type. The most common patterns were type 1 in the 2nd intermetacarpal space, type 2 in the 3rd intermetacarpal space, and type 3r in the 4th intermetacarpal space. And in the present study, we observed one case of the extensor digitorum brevis manus (EDBM) on the boht side. Conclusion: A knowledge of both the usual and possible variations of the extensor tendon and the intertendinous connection is useful in the identification and repair of these structures.