Earticle

본 연구는, 무선랜 네트워크 내에서 인프라 스트럭쳐가 제공하는 정보를 이용하여 에이전트 단말의 위치를 결정하는 위치정보 제공 시스템을 개발, 제시하였다. 본 시스템은 일반적인 ESS(Extended Service Set)형의 무선랜 구성에서 AP(Access Point) 컨트롤러를 통해 실시간 위치 측위 엔진을 구성하였으며, 측위 엔진은 SNMP(Small Network Management Protocol)을 이용하여, 각각의 AP에 접속하여 통신 패킷을 송수신하는 에이전트 단말의 정보를 AP 컨트롤러로부터 수집하여 위치 기반 서비스용 Cell ID.정보로 활용하게 된다. 실제 사무실 환경에서 구현해 본 결과, 평균 62.5%의 AP간 로밍 성공률을 보였으나 AP내 단말정보의 업데이트 시간은 평균 11초로서, 정확한 위치정보와 함께 긴급성이 덜 필요로 하는 위치기반 서비스에의 적용 가능성을 보였다.

In this paper, we propose the location determination system of an agent mobile device using the information provided by the WLAN(Wireless LAN) infrastructure. This system is configured as a typical ESS(Extended Service Set)-type WLAN structure with real-time location positioning engine and thru AP(Access Point) controller. The positioning engine collects the information of agent devices using SNMP(Small Network Management Protocol) thru AP controller and utilize those information as Cell ID. for LBS(Location Based Service). In the result of a real office environment implementation, the average success rate of inter-AP roaming is measured to 62.5% and the duration time of the device information update within the AP is average of 11 second of time, which means this system is adaptable to the location based service of above average accuracy but somewhat less urgency.

본 논문에서는 재난 상황에서 기존 상용 모바일 인프라(Mobile Infra)가 동작하지 않는 상태에서도 긴급하게 사용자에게 통 신망을 제공할 수 있는 솔루션에 대해 설명한다. 재난안전망 주파수가 아닌 일반 상용 주파수를 활용하여 요구조자까지 수용 가능한 구조로 설계하였으며, SW 기반의 범용 장비를 통해 개발하여 기존 솔루션보다 훨씬 작게 만들어 이동성을 확보하였다. 또한 대량의 단말의 접속도 수용 가능하도록 개발하였으며, 시험을 통해 재난에서 필요한 성능의 통신을 제공할 수 있음을 검증 하였다.

스마트폰과 모바일 환경이 발전하면서 개인의 업무 수행을 위한 시간과 공간의 제약이 사라지고 있다. 기업은 클라 우드 컴퓨팅을 통하여 비용을 절감하고 사업의 범위를 빠르게 확대할 수 있게 되었다. 다양한 클라우드의 사용이 확대되면 서 사용자, 데이터, 어플리케이션의 경계가 사라지고 있다. 경계(Perimeter)을 기준으로 하는 전통적인 보안 접근은 클라우 드 환경에서 효용을 잃어가고 있다. 이에, 본 논문에서는 클라우드 환경에서 기존 Network Access Control(NAC)의 한계를 기술하고 이를 보완한 네트워크 보안 기술을 제안한다. 관련연구로 SDP에 대해서 설명하고, NAC의 한계를 극복하기 위해 SDP(Software Defined Perimeter)를 융합하고 동시에 클라우드 환경의 지원을 위한 새로운 프레임워크로의 역할을 설명한 다. 본 논문에서 제안한 새로운 프레임워크는 물리적인 부분과 소프트웨어적인 부분에 SDP 기술을 적용하여 IP 기반이 아 닌 신원 중심 접근제어 제공, 암호화된 세그먼트 관리, 동적정책관리 등을 지원하는 소프트웨어 기반의 네트워크 보안 솔루 션을 제안한다.

As the smartphone and mobile environment develop, the time and space constraints for individual work performance are disappearing. Companies can reduce costs and expand their business quickly through cloud computing. As the use of various cloud expands, the boundaries of users, data, and applications are disappearing. Traditional security approaches based on boundaries (Perimeter) are losing their utility in the cloud environment. This paper describes the limitations of existing network access control (NAC) in a cloud environment and suggests network security technology that complements it. The study explains the SDP and combines SDP(Software Defined Perimeter) to overcome the limitations of NAC, while at the same time explaining its role as a new framework for supporting the cloud environment. The new framework proposed in this paper suggests a software-based network security solution that supports physical and software parts, providing identity-based access control, encrypted segment management, and dynamic policy management, not IP-based.

In the evolution of traditional telecom network towards a converged next generation network, Inter-working is always challenging due to different name spaces and routing mechanism across different communities. Most existing Inter-working solutions are terminal based solutions. They require mobile phone or PC users to install multiple client-side applications on the devices, such as, Google talk client, Skype client, and MSN client, etc. In order to avoid too many client applications running on mobile terminals that normally have a limited resource, a network based Inter-working solution is desired. An IMS based Inter-working solution for multi-media services is proposed. It enables an IMS subscriber make use of a single SIP user agent to communicate with the other users who might have communication means other than IMS based devices. The solution consists of two parts in the network: one is the conference like service that resides at the originating side and provides “forking service”; the other is the Inter-working gateway service that provides the protocol conversion service. The detailed technical description of the proposed solution is described hereafter. The corresponding use cases are studied. The application of the solution to the Group Communication service, e.g. an ad-hoc group or pre-defined group multimedia service, is also discussed. The benefits of the proposed solution for end users and operators are highlighted respectively.

Linear Programming(LP) is the term used for defining a wide range of optimization problems in which the objective function to be minimized or maximized is linear in the unknown variables and the constraints are a combination of linear equalities and inequalities. LP problems occur in many real-life economic situations where profits are to be maximized or costs minimized with constraint limits on resources. While the simplex method introduced in a later reference can be used for hand solution of LP problems, computer use becomes necessary even for a small number of variables. Problems involving diet decisions, transportation, production and manufacturing, product mix, engineering limit analysis in design, airline scheduling, and so on are solved using computers. This technique is called Sequential Linear Programming (SLP). This paper describes LP's problems and solves a LP's problems using the neural networks.

Recently, variety services are more and more developed due to supply of PDA, cellular phone, and etc. Also, a services based on location information are very helpful in traffic, shopping, and emergency. Thus the user position is positively necessary for these services. One of the latest applications in GPS is the E911 call service for wireless phones. In this case, current GPS Navigation accuracy meets the FCC requirements but the hardware size and power consumption of GPS is issued for implementation. And, some case of applications need to snapshot location solution with fast TTFF(Time-To-Fist-Fix) than continuous location solution. The software GPS receiver could be the solution ...

The concepts of graph theory are applied to model and analyze dynamics of computer networks, biochemical networks and, semantics of social networks. The analysis of dynamics of complex networks is important in order to determine the stability and performance of networked systems. The analysis of non-stationary and nonlinear complex networks requires the applications of ordinary differential equations (ODE). However, the process of resolving input excitation to the dynamic non-stationary networks is difficult without involving external functions. This paper proposes an analytical formulation for generating solutions of nonlinear network ODE systems with functional decomposition. Furthermore, the input excitations are analytically resolved in linearized dynamic networks. The stability condition of dynamic networks is determined. The proposed analytical framework is generalized in nature and does not require any domain or range constraints.

정보기술의 발달과 더불어 가상교육에 대한 연구가 활발하게 진행되고 있다. 실제 가상교육솔루션에 대한 개발 및 교육현장에서 많이 사용하고 있으나 그 선정 및 평가 방법에 대한 연구가 미비한 실정이다. 본 논문은 기 발표한 평가요인 결과를 사용하여 가상교육솔루션 평가 방법에 대하여 소개하고 있다. 기준들간의 영향관계가 있는 특성의 문제를 네트웍 모형으로 표현하는 것을 토대로 자료를 부여받고 선정하는 방법에 대한 과정을 제시하고 있다.

Computer has been many effect in diverse field of mankind and it brings development of educational field like CAI. Also development of internet and If bring rapid growth of cyber school and it is required multimedia environment and efficient cyber school construction package for efficient management. In this paper we develop multimedia education-network construction package for cyber school using intranet. It will reduce the cost of management and construction for small and medium size cyber school, and it will raise efficiency of cyber school.

This paper describes on the threats such as IP spoofing, denial of service, and ILMI based attack etc. for IP over ATM network. Especially we discuss on the threats due to ATM characteristics that are VC stealing, multiparty and multi-connection call. Also we investigate on the threats of ATM based MPLS network. Finally we discuss and suggest the various solutions of ATM security.