• 동굴
• /
• 제80호
• /
• pp.11-19
• /
• 2007

Most studies in the past in testing and benchmarking on Intrusion Detection System (IDS) were conducted as comparisons, rather than evaluation, on different IDSs. This paper presents the evaluation of the performance of one of the open source IDS, snort, in an inexpensive high availability system configuration. Redundancy and fault tolerance technology are used in deploying such IDS, because of the possible attacks that can make snort exhaust resources, degrade in performance and even crash. Several test data are used in such environment and yielded different results. CPU speed, Disk usage, memory utilization and other resources of the IDS host are also monitored. Test results with the proposed system configuration environment shows much better system availability and reliability, especially on security systems.

• 대한기계학회논문집B
• /
• 제29권6호
• /
• pp.755-762
• /
• 2005

To evaluate the aerodynamic efficiency of TR-S2 configuration designed by SUDC, wind tunnel tests of $40\%$ scaled model were done in KARI LSWT. The aerodynamic characteristics of plain and Semi-Slotted Flaperon were compared, and vortex generators were installed to improve flow pattern along the wing surface. Effects of the control surface such as elevator, rudder, aileron, and incidence angle of horizontal tail are measured for various testing conditions. Test results showed that Semi-Slotted Flaperon produced more favorable lift, lift/drag, and stall margins and application of vortex generator would be best choice to enhance wing performance. Longitudinal, lateral and directional characteristics of TR-S2 were found to be stable for the pitch and yaw motions.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제16권4호
• /
• pp.130-136
• /
• 2008

The refrigerant R-134a flow distributions are experimentally studied for a round header/ten flat tube test section simulating a brazed aluminum heat exchanger. Three different inlet orientations(parallel, normal, vertical) were investigated. Tests were conducted with downward flow for the mass flux from 70 to 130 $kg/m^2s$ and quality from 0.2 to 0.6. In the test section, tubes were flush-mounted with no protrusion into the header. It is shown that normal and vertical inlet yielded approximately similar flow distribution. At high mass fluxes or high qualities, however, slightly better results were obtained for normal inlet configuration. The flow distribution was worst for the parallel inlet configuration. Possible explanation is provided based on flow visualization results.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
• /
• pp.88-92
• /
• 2004

Most studies in the past in testing and benchmarking on Intrusion Detection System (IDS) were conducted as comparisons, rather than evaluation, on different IDSs. This paper presents the evaluation of the performance of one of the open source IDS, snort, in an inexpensive high availability system configuration. Redundancy and fault tolerance technology are used in deploying such IDS, because of the possible attacks that can make snort exhaust resources, degrade in performance and even crash. Several test data are used in such environment and yielded different results. CPU speed, Disk usage, memory utilization and other resources of the IDS host are also monitored. Test results with the proposed system configuration environment show much better system availability and reliability, especially on security systems.

• 한국항공우주학회지
• /
• 제49권9호
• /
• pp.721-727
• /
• 2021

본 논문에서는 아음속유동에서 그리드핀 유도무기의 공력특성을 실험적연구를 통하여 기술하였다. 그리드핀 형상에 의한 영향을 살펴보기 위해 폐쇄율을 달리한 그리드핀 형상모델을 이용하였다. 공기역학적특성을 살펴보기 위해 그리드핀 포함 유도무기 형상의 6성분 공기역학적 힘과 모멘트를 측정하여 레이놀즈수에 의한 영향, 그리드핀 형상에 의한 영향, 조종성능 등을 알아보았다.

• Advances in aircraft and spacecraft science
• /
• 제6권2호
• /
• pp.117-144
• /
• 2019

High Altitude and Long Endurance (HALE) aircraft are capable of providing intelligence, surveillance and reconnaissance (ISR) capabilities over vast geographic areas when equipped with advanced sensor packages. As their use becomes more widespread, the demand for additional range, endurance and payload capability will increase and designers are exploring non-conventional configurations to meet the increasing demands. One such configuration is the joined-wing concept. A joined-wing aircraft is one that typically connects a front and aft wings in a diamond shaped planform. One such example is the Boeing SensorCraft configuration. While the joined-wing configuration offers potential benefits regarding aerodynamic efficiency, structural weight, and sensing capabilities, structural design requires careful consideration of elastic buckling resulting from the aft wing supporting, in compression, part of the forward wing structural loading. It has been shown already that this is a nonlinear phenomenon, involving geometric nonlinearities and follower forces that tend to flatten the entire configuration, leading to structural overload due to the loss of the aft wing's ability to support the forward wing load. Severe gusts are likely to be the critical design condition, with flight control system interaction in the form of Gust Load Alleviation (GLA) playing a key role in minimizing the structural loads. The University of Victoria Center for Aerospace Research (UVic-CfAR) has built a 3-meter span scaled and flexible wing UAV based on the Boeing SensorCraft design. The goal is to validate the nonlinear structural behavior in flight. The main objective of this research work is to perform Ground Vibration Tests (GVT) to characterize the dynamic properties of the scaled flight vehicle. Results from the experimental tests are used to characterize the modal dynamics of the aircraft, and to validate the numerical models. The GVT results are an important step towards a safe flight test program.

• Computers and Concrete
• /
• 제29권1호
• /
• pp.31-45
• /
• 2022

Experimental and numerical simulation were used to investigate the effects of angle and number of T shape non-persistent crack on the shear behaviour of crack's bridge area under uniaxial compressive test. concrete samples with dimension of 150 mm×150 mm×40 mm were prepared. Within the specimen, T shape non-persistent notches were provided. 16 different configuration systems were prepared for T shape non-persistent crack based on two and three cracks. In these configurations, the length of cracks were taken as 4 cm and 2 cm based on the cracks configuration systems. The angle of larger crack related to horizontal axis was 0°, 30°, 60° and 90°. Similar to cracks configuration systems in the experimental tests, 28 models with different T shape non-persistent crack angle were prepared in numerical model. The length of cracks were taken as 4 cm and 2 cm based on the cracks configuration systems. The angle of larger crack related to horizontal axis was 0°, 15°, 30°, 45°, 60°, 75° and 90°. Tensile strength of concrete was 1 MPa. The axial load was applied to the model. Displacement loading rate was controlled to 0.005 mm/s. Results indicated that the failure process was significantly controled by the T shape non-persistent crack angle and crack number. The compressive strengths of the specimens were related to the fracture pattern and failure mechanism of the discontinuities. Furthermore, it was shown that the compressive behaviour of discontinuities is related to the number of the induced tensile cracks which are increased by increasing the crack number and crack angle. The strength of samples decreased by increasing the crack number. In addition, the failure pattern and failure strength are similar in both methods i.e. the experimental testing and the numerical simulation methods (PFC2D).

• 한국항행학회논문지
• /
• 제25권5호
• /
• pp.313-319
• /
• 2021

본 논문에서는 MIL-HDBK-344A 기반의 ESS(environmental stress screening) 시험 에 대해 소개하고, 유도탄 내부 케이블의 ESS 시험에 대한 목적과 규격 설정 및 시험 방안에 대하여 확인하였다. ESS 시험구성은 온도 순환과 랜덤 진동의 환경 자극으로 이루어져 있으며, 핸드북의 절차를 기반으로 유도탄 내부 케이블의 ESS 시험 규격 설정과 시험 구성을 제시하고, 진동 시험을 위한 유도탄 내부 케이블의 ESS 시험을 위한 치구를 제작하였다. 스크린 강도(SS; screening strength)를 통해 결정되는 결함 감지 확률은 일회성으로 사용되는 유도탄의 신뢰성에 부합되도록 선정하였고, 또한 ESS 시험 중 유도탄 내부 케이블의 검사방법과 고려해야 할 점에 대하여 소개하였다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.1453-1460
• /
• 2003

The present study investigates the effects of rib arrangements and aspect ratios of a rectangular duct simulating the cooling passage of a gas turbine blade. Two different V-shaped rib configurations are tested with the aspect ratios (W/H) of 3 to 6.82. One is the continuous V-shaped rib configuration with $60^{\circ}$ attack angle, and the other is the discrete V-shaped rib configuration with $45^{\circ}$ attack angle. The square ribs with the pitch to height ratio of 10.0 are installed on the test section in a parallel arrangement for both rib configurations. Reynolds numbers based on the hydraulic diameter are changed from 10,000 to 30,000. A naphthalene sublimation method is used to measure local heat/mass transfer coefficients. For the continuous V-shaped rib configuration, two pairs of counter-rotating vortices are generated in a duct, and high transfer region is formed at the center of the ribbed walls of the duct. However, for the discrete V-shaped rib configuration with $45^{\circ}$ attack angle, complex secondary flow patterns are generated in the duct due to its geometric feature, and more uniform heat/mass transfer distributions are obtained for all tested cases

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권3호
• /
• pp.1404-1415
• /
• 2016

Because of the properties of software such as invisibility, complexity, and changeability, software configuration management (SCM) for software artifacts generated during software life-cycle has been used for guarantee of the quality of the software. However, the existing SCM system has only focused on code artifacts and software development document artifacts such as Software Requirements Specification (SRS), Software Design Description (SDD), and Software Test Description (STD). Moreover, software research-oriented project comes out late the code artifacts and the software development document artifacts. Therefore, there is a need for trace and management of software research document artifacts composed of highly abstracted non-functional requirements like 'the purpose of the project', 'the objectives', and 'the progress' before generation of the code artifacts and the software development document artifacts for a long time. Nevertheless, the existing SCM system cannot trace and manage them. In this paper, we propose content-based configuration management system comprised of the relevance link generation phase and content-based testing phase to trace and manage them. The preliminary application results show applicability and feasibility of the proposed system.