• 한국기계가공학회지
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• 제16권3호
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• pp.38-44
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• 2017

The technology of electrical discharge tap machining may be appropriate for making thread out of highly brittle material. Especially, it is very difficult to machine tap with the traditional method if the brittle material has been hardened by quenching. In this study, the shape of electrical discharge blind hole tap machining was analyzed by discharge time, discharge current, and the flushing hole condition after quenched the tool steel of STD11 has discharged the tap shape with a screw-shaped copper(Cu) electrode. An experimental design was planned and analyzed by Taguchi robust experimental design. The result showed that the shape of the blind hole discharge tap was influenced by the flushing hole, discharge time, and discharge current. The most important factor of the processing conditions was found to be the discharge current. When blind hole EDM with a copper electrode with a flushing hole was conducted, the discharged shape was found to be smooth and the angle of the discharged tapped thread was also found to be close to the thread angle of $60^{\circ}$. As the values of discharge time and discharge current increased, the EDMed surface coarsened due to the increase of the single discharge energy and the shape of the thread collapsing.

• Steel and Composite Structures
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• 제23권1호
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• pp.115-130
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• 2017

A new type of moment-resisting bolted connection was developed for use in composite steel- concrete construction to connect composite open section steel beams to concrete filled steel square tubular columns. The connection was made possible using anchored blind bolts along with two through bolts. It was designed to act compositely with the in-situ reinforced concrete slab to achieve an enhanced stiffness and strength. The developed connection was incorporated in the design of a medium rise (five storey) commercial building which was located in low to medium seismicity regions. The lateral load resisting system for the design building consisted of moment resisting frames in two directions. A major full scale test on a sub-assembly of a perimeter moment-resisting frame of the model building was conducted to study the system behaviour incorporating the proposed connection. The behaviour of the proposed connection and its interaction with the floor slab under cyclic loading representing the earthquake events with return periods of 500 years and 2500 years was investigated. The proposed connection was categorized as semi rigid for unbraced frames based on the classification method presented in Eurocode 3. Furthermore, the proposed connection, composite with the floor slab, successfully provided adequate lateral load resistance for the model building.

• 한국태양에너지학회 논문집
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• 제30권6호
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• pp.1-9
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• 2010

Apartment balcony has been remodeled since the government permitted remodeling in January 2006.But extended balcony has great impact on building heat gain and loss. Therefore It has problems such as increase of heating and cooling energy. So $\underline{t}echnical$ solutions about window solar gain in summer is an urgent matter. The Purpose of this study is to evaluate energy performance of a blind in a double-skin facade in residential buildings by using EnergyPlus program. The results show that slat angles of $90^{\circ}$ is best in energy performance if we do not consider daylight. Poorly daylighted living room needs electric light and it also causes high cooling load. On the other hand, the results show that the application of blinds controlled automatically is best for energy performance when we consider daylight. Blind slat angles of $50\sim60^{\circ}$ have best performance when blinds are controlled in this angle throughout the day on a clear day in August. Blind slat angles of $0\sim30^{\circ}$ have best performance when blinds $\underline{are\;controlled}$ in this angle throughout the day on a cloudy day (more than 7 of total sky cover) in August.

• 생명과학회지
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• 제26권8호
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• pp.936-942
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• 2016

본 연구는 초피의 항균 활성 소재의 산업화 타진 연구로 초피과피 정유 성분의 경우 높은 생산단가로 인해 그 활용이 제한적이다. 이에 초피잎을 대상으로 항균 활성소재를 탐색하고 초피의 천연 방향성과 항균력을 이용하여 실내 환경 개선 소재 특히 친환경 항균블라인드 개발에 대한 활용 가능성을 타진하였다. 그 결과, 초피잎 추출물의 항균 활성은 초피과피 추출물보다 약하게 나타났지만, K. pneumoniae, S. aureus와 S.mutans 균에 대하여 IC₅₀ 값은 0.5 mg/ml, 0.1 mg/ml와 1.0 mg/ml로 운향과 유래 타 Zanthoxylum 속 보다 항균력이 강한 것으로 나타났다. 항균력이 강하게 확인된 초피잎 EtOH 추출물과 EtOAc 추출물의 GC-MS 분석을 통해 초피잎 유래의 항균력 관련 화합물로서 quinic acid, 3,5-dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one과 kaempferol 등을 확인할 수 있었다. 또한, International Standard Fabrics Test Method에 준하여 초피 추출물을 처리한 블라인드 소재의 항균력을 조사한 결과, 1% 농도의 초피잎 EtOH 추출물을 처리한 직물 블라인드 소재의 경우는 항생제 내성균 S. aureus의 생육을 99.9% 저해하였고, 2% 농도의 처리에 의해서는 K. pneumoniae 생육도 완전히 저해하였다. 이러한 연구결과는, 고가인 초피과피에 비해 농산폐자원으로 폐기되고 있는 초피잎의 항균력을 이용하여 친환경 기능성 항균 직물 블라인드 및 실내 창호 소재를 개발한다면 최근 급증하는 실내 환경성 질환의 예방 및 제어에 매우 유용할 수 있음을 시사한다.

• 로봇학회논문지
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• 제13권1호
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• pp.38-44
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• 2018

In this paper, we propose Intelligent Driver Assistance System (I-DAS) for driver safety. The proposed system recognizes safety and danger status by analyzing blind spots that the driver cannot see because of a large angle of head movement from the front. Most studies use image pre-processing such as face detection for collecting information about the driver's head movement. This not only increases the computational complexity of the system, but also decreases the accuracy of the recognition because the image processing system dose not use the entire image of the driver's upper body while seated on the driver's seat and when the head moves at a large angle from the front. The proposed system uses a convolutional neural network to replace the face detection system and uses the entire image of the driver's upper body. Therefore, high accuracy can be maintained even when the driver performs head movement at a large angle from the frontal gaze position without image pre-processing. Experimental result shows that the proposed system can accurately recognize the dangerous conditions in the blind zone during operation and performs with 95% accuracy of recognition for five drivers.

• 한국산학기술학회논문지
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• 제14권4호
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• pp.1951-1956
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• 2013

랜덤 순서로 발생된 심볼 열을 기반으로 하는 확률 분포 매칭 타입의 알고리듬들은 그 성능 기준이 바이어스된 신호에 대한 변수를 지니고 있지 않아서 바이어스된 충격성 잡음 하에서는 제한된 성능을 나타낸다. 이 논문에서는 바이어스된 충격성 잡음을 이겨내기 위한 수정된 성능기준을 제안하고, 증강된 필터구조와 랜덤 심볼 열을 사용하는 확률 분포 매칭 방법에 기초한 블라인드 알고리듬을 제안하였다. 시뮬레이션 결과로부터 제안된 성능기준에 의해 만들어진 제안된 알고리듬이 바이어스된 강한 충격성 잡음에 대해 동요됨이 없이 탁월한 수렴성능을 보였다.

• Steel and Composite Structures
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• 제34권6호
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• pp.803-818
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• 2020

Semi-rigid connections with blind bolts could solve the difficulty that traditional high strength bolts were unavailable to splice a steel/composite beam to a closed section column. However, insufficient investigations have focused on the performance of semi-rigid connection to square concrete filled double-skin steel tubular (CFDST) columns. In this paper, a component model was developed to evaluate the mechanical behavior of semi-rigid composite connections to CFDST columns considering the stiffness and strength of column face in compression and column web in shear which were determined by the load transfer mechanism and superstition method. Then, experimental investigations on blind bolted composite joints to square CFDST columns were conducted to validate the accuracy of the component model. Dominant failure modes of the connections were analyzed and this type of joint behaved semi-rigid manner. More importantly, strain responses of CFDST column web and tubes verified that stiffness and strength of column face in compression and column web in shear significantly affected the connection mechanical behavior owing to the hollow part of the cross-section for CFDST column. The experimental and analytical results showed that the CFDST column to steel-concrete composite beam semi-rigid joints could be employed for the assembled structures in high intensity seismic regions.

• IEIE Transactions on Smart Processing and Computing
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• 제4권6호
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• pp.413-421
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• 2015

Regularized Blind Deconvolution is a problem applicable in degraded images in order to bring the original image out of blur. Multichannel blind Deconvolution considered as an optimization problem. Each step in the optimization is considered as variable splitting problem using an algorithm called Alternating Minimization Algorithm. Each Step in the Variable splitting undergoes Augmented Lagrangian method (ALM) / Bregman Iterative method. Regularization is used where an ill posed problem converted into a well posed problem. Two well known regularizers are Tikhonov class and Total Variation (TV) / L2 model. TV can be isotropic and anisotropic, where isotropic for L2 norm and anisotropic for L1 norm. Based on many probabilistic model and Fourier Transforms Image deblurring can be solved. Here in this paper to improve the performance, we have used an adaptive regularization filtering and isotropic TV model Lp norm. Image deblurring is applicable in the areas such as medical image sensing, astrophotography, traffic signal monitoring, remote sensors, case investigation and even images that are taken using a digital camera / mobile cameras.

• 한국태양에너지학회 논문집
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• 제34권5호
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• pp.89-99
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• 2014

The determination of the solar and thermal performance of fenestration is required for the evaluation of fenestration energy performance, estimating building load. Presently, there exist several methods for determining the thermal transmission(U-value) and solar heat gain coefficient (SHGC) of fenestration system. These method are commonly grouped under calculation or experimental methods. While U-value testing and calculation methods have been long established, SHGC has been evaluated only by the method of calculation under the lack of any established testing method. However, it is difficult to assess the exact SHGC for various types of fenestration with sun-shading or other solar control systems. The purpose of this study was to evaluate the effect of interior venetian blind and roll screen on the SHGC of glazing system. SHGC has been evaluated by the KS L 9107 test method and exiting calculation method for precise comparison of the energy performances of various shading devices. In this research, the test sample consists of three different types of double glazing unit with venetian blind and roll screen. Slat angles of venetian blind were changed to $-45^{\circ}$, $0^{\circ}$, and$-45^{\circ}$. For the roll screen, measurements were taken with the roll screen in the closed position. In result, the venetian blind reduced SHGC by 21.2~28.4% at $45^{\circ}$, when compared to the double glazing unit. The roll screen reduced SHGC by 34.4~41.7% at closed. The differences between the measured and calculated SHGC were found to range between 0.001(0.2%) and 0.047(11.1%) for all test cases. For the cases of venetian blind $-45^{\circ}$, $0^{\circ}$ and $45^{\circ}$, the deviation ratio were 3.6~9.8%, 1.1~2.6%, 4.2~11.1%, respectively. For the case of roll screen, the deviation ratio were 4.1~5.7%.

• KIEAE Journal
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• 제15권4호
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• pp.69-76
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• 2015

Purpose: This study is to investigate the effects of facade insulation and window remodeling of an existing old middle school building on the reduction of energy consumption. Method: To analyze energy performance of building, using DesignBuilder v3.4, building energy simulation tool based EnergyPlus engine. Energy consumption and problem of target building was analyzed based on data and survey. Based on building energy simulations it analyzed the variation of energy demand for the building according to U-value of wall, glazing properties and external shading devices. Result: When insulation of building was reinforced, cooling and heating load was decreased. Glazing properties that minimize cooling and heating energy consumption were analyzed. In conclusion, it is important to choose SHGC and U-value of window fit in characteristic of target building. Setting external blind for cooling load decreases 5%.