• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1881-1884
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• 2003

In this experiment, the oxidations of p-Xylene (140-180 ppmv), one of the air pollutants as a VOC, using $UV/TiO_2$ photocatalyst is studied. In order to increase the specific surface area, the filter is coated by nano $TiO_2$ particles. The photodegradation system consists of a VOCs generator, a photocatalyst filter and a measuring equipment. Illumination is generally provided by two of 20 W black light lamps with 380 nm of wavelength. The filter coated by nano $TiO_2$ particles has a passing efficiency over 80% but a pressure drop of 9.0 $mmH_2O$ at 0.45 cm/s. The filter endurance is better than activated carbon at the same pressure drop.

• 한국전기전자재료학회논문지
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• 제27권1호
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• pp.61-69
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• 2014

In this paper, we have researched semiconductor optical filters to solve the problem of the high failure rate that are recognize bad of financial account, jam of financial account and the ATM service interruption due to failure of accurate location information among the operation of the ATM (automatic teller machine) systems. A semiconductor optical filters that have high resolution and less diffuse, high transmittance are able to detect the information of financial account surface accurately. Therefore, it is a stable filter that is able to minimize the incidence of disability. In this paper, we drew the determinants by element for implement an excellent semiconductor optical filters. Based on this, we had to be able to implement the semiconductor optical filter that is able to be mounted on the actual ATM system through future studies.

• 한국연초학회지
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• 제24권1호
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• pp.46-52
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• 2002

This study was carried out to investigate the transfer rate of I-menthol constituent into cigarette case and delivery rate to cigarette smoke. Test sample was used a light-type standard brand cigarette made in Korea. I-Menthol contents was measured according to A.O.A.C(1990) method by G.C and smoking conditions was a puff volume of 35$m\ell$ and 2.0s duration, taken once per minute to filter tipping paper plus 3mmwith 20 cigarettes. Migration rate of menthol into cigarette case had an interrelation with triacetin contents into filter and 6% triacetin level was most suitable. I-Menthol transferred to filter part from tobacco sheet by 20.2% in one month after cigarette manufacture, and the transfer was continued subsequently. Maximum menthol transfer in five months was 4.1% to foils and other packing materials and the loss outside of cigarette pack was also 3.9% below. The migration balance of menthol into cigarette pack and the delivery to cigarette smoke were the optimum condition when menthol was added at the ration of 30% in filter to 70% in the other parts into cigarette.

• 한국정보통신학회논문지
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• 제11권10호
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• pp.1894-1898
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• 2007

본 연구는 산업체에서 널리 사용되어지고 있는 기존의 3상 AC-DC 컨버터에서 무게와 부피를 획기적으로 줄일 수 있는 고역율 3상 AC-DC컨버터를 제안하였다. 제안된 고역율 3상 AC-DC 컨버터는 LC 필터를 제거 한 상태에서 효율성과 다탕성을 검증함으로써 경량화는 물론 저 비용을 실현할 수 있게 된다. 또한 LC 필터를 제거하였음에도 불구하고 성능 면에서 볼 때 기존의 AC-DC 컨버터와 비슷한 성능을 얻을 수 있으므로 고전력 밀도 및 고역율이 요구되는 항공 우주 분야에 응용이 가능해 질 것으로 기대된다.

• 한국컴퓨터정보학회논문지
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• 제24권6호
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• pp.1-9
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• 2019

Hard disks, which have long been used as secondary storage in computing systems, are increasingly being replaced by solid state drives (SSDs), due to their relatively fast data input / output speeds and small, light weight. SSDs that use NAND flash memory as a storage medium are significantly different from hard disks in terms of physical operation and internal operation. In particular, there is a feature that data overwrite can not be performed, which causes erase operation before writing. In order to solve this problem, a hot data for frequently updating a data for a specific page is distinguished from a cold data for a relatively non-hot data. Hot data identification helps to improve overall performance by identifying and managing hot data separately. Among the various hot data identification methods known so far, there is a technique of recording consecutive write requests by using a Bloom filter and judging the values by hot data. However, the Bloom filter technique has a problem that a new bit array must be generated every time a set of items is changed. In addition, since it is judged based on a continuous write request, it is possible to make a wrong judgment. In this paper, we propose a method using a counting filter for accurate hot data verification. The proposed method examines consecutive write requests. It also records the number of times consecutive write requests occur. The proposed method enables more accurate hot data verification.

• Transactions on Electrical and Electronic Materials
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• 제12권6호
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• pp.253-257
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• 2011

This study was carried out to solve problems such as radio frequency band depletion, confusion risk, and security loss in existing visible wireless communication systems, and to determine the applicability of next-generation networks. A light-emitting diode (LED) light communication system was implemented with a controlling switching light module using the ATmega16 micro-controller. To solve the existing modulation effect and disturbance in visible light communication, an integrated interface was evaluated with a driving light module and analyzes its reception property. A transmitter/receiver using the ATmel's micro-controller, high-intensity white LED-6 modules, and infrared sensor KSM60WLM and visible sensor TSL250RD were designed. An experiment from the initial value of distance to 2.5 m showed 0.46 V of the voltage loss, and if in long distance, external light interference occurred and light intensity was lost by external impact and thus data had to be modified or reset repeatedly. Additionally, when we used 6 modules through the remote controller's lighting dimming, data could be transmitted up to 1.76 m without any errors during the day and up to 2.29 m at night with around 2~3% communication error. If a special optical filter can reduce as much external light as possible in the integrated interface, the LED for lighting communication systems may be applied in next generation networks.

• 제어로봇시스템학회논문지
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• 제7권8호
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• pp.656-663
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• 2001

This paper presents a sensor fusion method to recognize a cylindrical object a CCD camera, a laser slit beam and ultrasonic sensors on a pan/tilt device. For object recognition with a vision sensor, an active light source projects a stripe pattern of light on the object surface. The 2D image data are transformed into 3D data using the geometry between the camera and the laser slit beam. The ultrasonic sensor uses an ultrasonic transducer array mounted in horizontal direction on the pan/tilt device. The time of flight is estimated by finding the maximum correlation between the received ultrasonic pulse and a set of stored templates - also called a matched filter. The distance of flight is calculated by simply multiplying the time of flight by the speed of sound and the maximum amplitude of the filtered signal is used to determine the face angle to the object. To determine the position and the radius of cylindrical objects, we use a statistical sensor fusion. Experimental results show that the fused data increase the reliability for the object recognition.

• The Korean Journal of Physiology and Pharmacology
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• 제13권3호
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• pp.221-227
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• 2009

For successful restoration of visual function by a visual neural prosthesis such as retinal implant, electrical stimulation should evoke neural responses so that the informat.ion on visual input is properly represented. A stimulation strategy, which means a method for generating stimulation waveforms based on visual input, should be developed for this purpose. We proposed to use the decoding of visual input from retinal ganglion cell (RGC) responses for the evaluation of stimulus encoding strategy. This is based on the assumption that reliable encoding of visual information in RGC responses is required to enable successful visual perception. The main purpose of this study was to determine the influence of inter-dependence among stimulated RGCs activities on decoding accuracy. Light intensity variations were decoded from multiunit RGC spike trains using an optimal linear filter. More accurate decoding was possible when different types of RGCs were used together as input. Decoding accuracy was enhanced with independently firing RGCs compared to synchronously firing RGCs. This implies that stimulation of independently-firing RGCs and RGCs of different types may be beneficial for visual function restoration by retinal prosthesis.

• 디지털콘텐츠학회 논문지
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• 제10권1호
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• pp.121-127
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• 2009

자동차 ECU(Electronic Control Unit)는 날이 갈수록 더욱 복잡해지고 많은 기능을 요구하고 있다. 대표적으로 power windows switch, LCM(Light Control Module), mirror control system, seat memory등 운전자 편의 시스템이 개발되어 양산 중에 있다. 또한 현재 업계에서 많은 연구개발이 진행되고 있는 운전자 편의를 위한 DIS(Driver Information System)도 있다. 하지만 이러한 시스템을 운전 중 조작하게 되면 많은 위험이 따른다. 따라서 본 논문에서는 이러한 자동차 편의장치를 음성으로 조작 가능한 음성인식 시스템을 구현하였으며 자동차 잡음환경에서 인식률 향상을 위한 전처리 필터를 적용하여 양호한 인식결과 얻었다.

• 스마트미디어저널
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• 제7권4호
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• pp.24-29
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• 2018

딥러닝에서 자연어 처리를 위한 텍스트 분석 기법은 워드 임베딩을 통해 단어를 벡터 형태로 표현한다. 본 논문에서는 워드 임베딩 기법과 딥러닝 기법을 이용하여 SMS 문자 메시지를 문서 벡터로 구성하고 이를 스팸 문자 메시지와 정상적인 문자 메시지로 분류하는 방법을 제안하였다. 유사한 문맥을 가진 단어들은 벡터 공간에서 인접한 벡터 공간에 표현되도록 하기 위해 전처리 과정으로 자동 띄어쓰기를 적용하고 스팸 문자 메시지로 차단되는 것을 피하기 위한 목적으로 음절의 자모를 특수기호로 왜곡하여 맞춤법이 파괴된 상태로 단어 벡터와 문장 벡터를 생성하였다. 또한 문장 벡터 생성 시 CBOW와 skip gram이라는 두 가지 워드 임베딩 알고리즘을 적용하여 문장 벡터를 표현하였으며, 딥러닝을 이용한 스팸 문자 메시지 필터링의 성능 평가를 위해 SVM Light와 정확도를 비교 측정하였다.