• Convergence Security Journal
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• v.3 no.1
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• pp.73-84
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• 2003

The IPv4 that used to be generally used as a medium of computer communications in 1980s has reached its limits now. IPv6 (IP Version 6) is being prepared to solve the limitations of the IPv4. However, the biggest problem of IPv6 is that it is not compatible with the IPv4. To resolve the compatibility issue, Dual Stack, Tunneling and Header Converting methods have been proposed. The Header Converting method allows communications between the IPv4 and IPv6 networks with the converter. This method's strength is that it is easy to embody and the procedures for embodiment is simple. However, this method still contains the weaknesses that the existing IPv4 has. On the current document, the Header Converting method among the three methods is discussed to resolve the problems this method has. To solve the Header Converting method's weakness, the security problem between sections, the IP Header field values are converted to the relative field values and IPSec (IP Security) and ESP (Encapsulation Security Payload) are applied. The proposed "Encrypted Header Converting Method" that is encrypted in packet units has solved the weakness that the pre-existing Header Converting method used to have.d to have.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.1
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• pp.1-10
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• 1998

A header is the device that makes uniform flow distribution in all branches from header of heat exchangers, pipe burner or chemical equipments. In this study, experimental tests have been performed in order to investigate the flow distribution characteristics in a straight header and tapered header which have 6 and 11 glass pipe branches. The experimental equipment consists of a water circulation system where the fluid velocity in each glass pipe is measured by Ar-ion LDV system. From the experiments and the theoretical equation, it could be recommended that tapered header should be determined so that its internal velocities inside the header become uniform according to taper of the header and number of attached branches for uniform flow distribution in energy systems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.11
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• pp.559-566
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• 2015

The main objective of this work is to experimentally investigate the effect of angle variation on the distribution of two-phase flow at header-channel junctions. The cross-sections of the header and the channels were fixed at $16mm{\times}16mm$ and $12mm{\times}1.8mm$, respectively. Air and water were used as the test fluids. Four different header-channel positions were tested : Vertical header with Horizontal channels (case VM-HC), Horizontal header with Horizontal channels (case HM-HC), Horizontal header with Vertical Downward channels (case HM-VDC), and Horizontal header with Vertical Upward channels (case HM-VUC). In all cases, liquid flow distribution tended to decrease gradually in the upstream header region. However, in the downstream region, different trends could be seen. The reason for these different tendencies were identified by flow visualization in each case. The standard deviations for the liquid and gas flow distribution in each case were calculated, and the case of VM-HC had the lowest values compared to other cases because of the symmetrically distributed liquid film and strong flow recirculation near the end plate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.27-30
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• 2012

In the Cluster-Based Routing Protocol (CBRP) a cluster header in each cluster should be elected. The cluster headers consume energy much more than other nodes because they manage and operate all of mobile nodes in their cluster. The traditional CBRP elects a cluster header without considering the remaining electric energy of each node. So, there exists problems that the cluster header has short average lifetime, and another cluster header should be elected again frequently. In this paper, we propose the improved protocol which prolongs the lifetime of the cluster header, decreases of header re-elected problem, decreases of header re-elected problem and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining electric energies of all the nodes are compared with one another, and the node with the highest energy is elected as the cluster header. Also, the node with the second highest energy is elected as the second header. If the elected cluster header is unable to perform the role of the cluster header because the remaining energy level goes low, it sends a beacon message to neighbor member nodes and the second header will serve as the cluster header.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.8 s.251
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• pp.780-787
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• 2006

Several types of different header designs are numerically studied to have uniform distribution of two phase flow in the evaporator header having multi-channels. The different geometries include the inlet tube position into the header and the width of header. In the numerical calculation, two types of two-phase model such as homogeneous model and VOF(Volume Of Fluid) model are employed. In this study, the mal-distribution number, $M_d$, is newly defined to evaluate the averaged level of the flow distribution in the whole passes of the evaporator. As results, two phase flow in the header can be visualized using post-processing of numerical results. Furthermore, the optimum position of the inlet tube into the header and the width of header can be proposed for the better distribution of refrigerant(R-134a) flow.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.831-834
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• 2011

LEACH(One of the leading algorithms in the field of WSN) for the life of the system, even by the number of all nodes to ensure that the cluster header. However, each round does not guarantee a certain number of cluster header. So sometimes cluster header is elected of small number or not elected. If cluster header number is to small, takes a heavy load on cluster header. And empty cluster is occur depending on the location of the cluster header. The algorithm proposed in this paper, the area of interest is divided into sectors. And randomly, cluster header be elected one the in each sector. When clustering the sensor nodes will belong to the nearest cluster header. So clustering is independent of the sector. This algorithm is guarantee a certain number of cluster header in each round. And has prevent occurrence of empty cluster.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.5A
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• pp.773-778
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• 2001

인터넷이 본격적으로 상업망으로 전화되고 보편화됨에 따라 인터넷 수요가 급격히 증가될 것으로 예상되고 있다. 이에 따른 빠른 전송과 서비스를 만족시키기 위한 포워딩 기술로써 MPLS에 대한 연구가 활발히 진행되고 있다. 본 논문은 MPLS 영역에서 IP 패킷의 성능이 병목 지역에서 레이블된 것과 레이블 되지 않은 패킷에 따라 어떤 성능을 보이는지를 분석하였다. 링크의 대역폭이 병목지역에서 발생된 패킷 발생률보다 더 작을 경우에는 오히려 시간이 지남에 EK라 MPLS 레이블된 경우에 레이블 오버헤드와 빠른 스위칭이 더욱 혼잡을 발생시켜 레이블 되지 않은 IP 패킷보다 성능이 저하되었다. 이러한 현상에 대한 해결책으로 본 논문은 MPLS shim header 부분에 대한 overhead를 레이블 스위칭 할 때 IP 라우팅을 사용하지 않는 동안 사용되지 않는 필드인 IP header의 주소 필드를 이용하는 새로운 MPLS shim header 할당 알고리즘을 제안하였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.4
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• pp.449-455
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• 1998

A header' is the device that makes uniform flow distribution in all branches from header of heat exchangers, pipe burner or chemical equipments. In this study, experimental tests have been performed in order to investigate the flow distribution characteristics in a straight header and tapered header which have 6 and 11 glass pipe branches. The experimental equipment consists of a water circulation system where the fluid velocity in each glass pipe is measured by Ar-ion LDV system. From the experiments and the theoretical equation, it could be recommended that tapered header should be determined so that its internal velocities inside the header become uniform according to taper of the header and number of attached branches for uniform flow distribution in energy systems.

• Proceedings of the Korean Society for Information Management Conference
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• 1996.08a
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• pp.75-78
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• 1996

본 연구는 TEI를 기반으로 한 전자문헌의 서지정보를 수록한 TEI Independent Header를 MARC으로 변환시켜 주기 위하여 전자문헌의 인코딩, 인코딩언어인 SGML, 인코딩 포맷인 TEI를 연구하였다. 나아가 TEI를 기반으로 한 전자문헌의 자동 목록작성의 가능성을 살펴보기 위하여 TEI Independent Header와 MARC을 비교분석하였다.

• Journal of the Korea Society of Computer and Information
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• v.18 no.1
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• pp.63-71
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• 2013

In the Cluster-Based Routing Protocol (CBRP) a cluster header in each cluster should be elected. The cluster headers consume energy much more than other member nodes do because they manage and operate all of mobile nodes in their cluster. The traditional CBRP elects a cluster header without considering the remaining electric energy of each node. So, there exist problems that the cluster header has short average lifetime, and a new cluster header should be elected again frequently. In this paper, we propose the improved protocol which prolongs the lifetime of the cluster header, decreases the problem of re-electing the cluster header and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining electric energies of all the nodes are compared with one another, and the node with the highest energy is elected as the cluster header. Also, the node with the second highest energy is elected as the second header. If the elected cluster header is unable to perform the role of the cluster header any more because the remaining energy level goes low, it sends a beacon message to neighbor member nodes, then the second header will serve as the cluster header.