• 정보보호학회논문지
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• 제31권4호
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• pp.753-762
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• 2021

웹 어셈블리는 웹 환경에서 수행 가능한 명령어 형식을 일컫는다. 최근 웹 어셈블리의 성능적인 우수함 때문에 다양한 웹 애플리케이션에서 웹 어셈블리가 활용되고 있다. 하지만 본 논문에서는 보안 관점에서 웹 어셈블리의 간접호출 명령어에 대한 보호 기능에 취약한 부분이 있다는 것을 알게 되었고, 이에 이러한 웹 어셈블리에서의 간접호출 명령어의 보호를 위한 코드 계측 기술인 WACFI를 제안한다. 구체적으로 WACFI에서는 소스 코드 분석을 통해 얻은 정보를 활용해 웹 어셈블리 코드를 수정하여 웹 어셈블리의 간접호출 명령어 보호 기능을 강화하였다. 우리의 실험결과에 따르면 WACFI는 단지 약 2.75%의 성능 부하만으로 이러한 보안 기능을 제공하는 것으로 확인되었다.

• 한국빅데이터학회지
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• 제4권2호
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• pp.13-22
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• 2019

이 연구는 2018년도 정부(농림축산식품부)의 재원으로 농림식품기술기획평가원 지원을 받아 수행된 연구이다. 고병원성 조류인플루엔자의 유입은 해외로부터 철새를 통해 유입되고 있으나 어떤 경로를 통해 감염 원인을 농장에 제공하는지 정확히 밝혀진 바 없다. 그리고 발생 농장으로부터 농장 간의 전이도 차량이 주 원인이라고 추정할 뿐, 전파 주 원인이 정확히 밝혀진 것은 아니다. 본 논문 연구에서는 KT가 제공하는 CDR(Call Detailed Record) 데이터를 기반으로, 발생후보지로 추정되는 철새도래지를 방문한 사람이 어떤 경로를 거쳐 감염 농장으로 유입이 되는지 해당 시기의 인구 흐름을 보려고 한다.

• 한국통신학회논문지
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• 제27권1C호
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• pp.36-47
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• 2002

MGCP는 IETF에서 제안한 VoIP기술의 표준 프로토콜로서 다른 프로토콜과의 연동이 용이하도록 설계되었으며, 현재 다양한 이기종 시스템과 프로토콜로 구성되어 있는 망을 통합하기 위한 적절한 해결책으로 부각되고 있다. 본 논문에서는 MGCP 호 제어를 담당하는 외부 시스템(MGC)으로부터 VoIP 게이트웨이를 제어하기 위해 사용된다. 또한 MGCP기반의 다양한 게이트웨이 시스템에서 다양한 MGC에 대해 호환성을 향상시키기 위한 방법에 대해 소개한다. 특히 메시지의 흐름(call flow)이나 인코딩 방식과 같은 각 MGC에 종속적인 부분에 있어서 호환성을 지원하기 위해 고려되어야 할 사항과 이를 해결하기 위한 방법에 대해 소개하고 성능 평가를 하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.465-470
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• 1998

A cross-flow fan often generates discrete noise call blade passing frequency tones. Several methods have been investigated to reduce this BPF noise, where the random distribution of blades is the most promising one. A simple and effective algorithm to determine a random distribution of blades is proposed which considers fan. performance as well as noise characteristics. The proposed method is verified by a simple numerical model and is applied in manufacturing cross-flow fan samples. Also some experiments are carried out and the experimental results are analyzed.

• 대한수학회보
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• 제38권2호
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• pp.337-346
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• 2001

A linearization owing to Oseen originally is performed to study the recirculating Navier-Stokes flows at high Reynolds numbers. The procedure is generalized to produce higher order asymptotic expansion for the flow velocity. We call this the Oseen-type expansion of the given flow. As a concrete example, the velocity of a steady Navier-Stockes flow due to a swimming flexible sheet in two-dimensional infinite strip domain is calculated by an asymptotic expansion technic with two-parameters, the Reynolds number R and the perturbation parameter $\varepsilon$ first and then R secondly. The asymptotic result is up to second order in $\varepsilon$.

• Journal of Communications and Networks
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• 제12권6호
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• pp.568-576
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• 2010

The paper presents a control architecture aimed at implementing bandwidth optimization combined with call admission control (CAC) over a digital video broadcasting (DVB) return channel satellite terminal (RCST) under quality of service (QoS) constraints. The approach can be applied in all cases where traffic flows, coming from a terrestrial portion of the network, are merged together within a single DVB flow, which is then forwarded over the satellite channel. The paper introduces the architecture of data and control plane of the RCST at layer 2. The data plane is composed of a set of traffic buffers served with a given bandwidth. The control plane proposed in this paper includes a layer 2 resource manager (L2RM), which is structured into decision makers (DM), one for each traffic buffer of the data plane. Each DM contains a virtual queue, which exactly duplicates the corresponding traffic buffer and performs the actions to compute the minimum bandwidth need to assure the QoS constraints. After computing the minimum bandwidth through a given algorithm (in this view the paper reports some schemes taken in the literature which may be applied), each DM communicates this bandwidth value to the L2RM, which allocates bandwidth to traffic buffers at the data plane. Real bandwidth allocations are driven by the information provided by the DMs. Bandwidth control is linked to a CAC scheme, which uses current bandwidth allocations and peak bandwidth of the call entering the network to decide admission. The performance evaluation is dedicated to show the efficiency of the proposed combined bandwidth allocation and CAC.

• 한국분무공학회지
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• 제10권4호
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• pp.26-31
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• 2005

Today, the research to examine a fact that interaction between the air and the fluid free surface affects the steady state flow and air. We proved the interaction between vortex pairs and free surface on each condition that is created by the end of delta wings. Another purpose of this study is to investigate the effect of surface active material which call change the surface tension and we must consider when we refer to turbulent flow on surface tension. Therefore, this research examined the growth process of vortex pairs on condition of clean, contaminated free surface and wall after we made vortex pairs through counter rotating flaps. The results of this study suggest that vortex pairs in clean free surface rise safely but the vortex pairs in contaminated free surface and rigid, no slip is made secondary vortex or rebounding. However the secondary vortex in rigid, no slip is stronger than before. and we can find the vortex shape which roll up more completely. However, these will disappear by the effect of wall.

• 한국컴퓨터정보학회논문지
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• 제21권6호
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• pp.77-81
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• 2016

This paper deals with the optimization problem that decides the routing of connection between multi-source and multi-sink. For this problem, there is only in used the mathematical approach as linear programming (LP) software package and has been unknown the polynomial time algorithm. In this paper we suggest the heuristic algorithm with $O(mn)^2$ time complexity to solve the optimal solution for this problem. This paper suggests the simple method that assigns the possible call flow quantity to augmenting path of ($s_i,t_i$) city pair satisfied with demand of ($s_i,t_i$). The proposed algorithm can be get the same optimal solution as LP for experimental data.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2012년도 춘계학술발표대회
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• pp.1213-1214
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• 2012

Global variables can be read or modified by any part of the program, making it difficult to remember or reason about every possible use. Sometime it has tight couplings between some of other variables, and couplings between variables and functions. The main focus of this paper is to use call graph and the control flow analysis to design a model from where we generate the test cases for testing global variables.

• 한국정밀공학회지
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• 제19권1호
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• pp.143-149
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• 2002

Robot are necessary to automate the work on a vertical plane of work piece to produce a large structure like a ship, so that a permanent magnet wheel has been attempted to be used for a mobile robot. Its adhesive power was enhanced by restricting the occurrence direction of magnetic flow. Furthermore a method which weakened the adhesive force was developed for easy detachement of the wheel by changing magnetic flow with metal pin. To measure the characteristics of the adhesive and detaching farces, a load call and a gaussmeter were used. The result showed that the adhesive power was reduced to 1/3 of normal state by using 4 inducing pins.