• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.72.2-72.2
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• 2013

An off-axis telescope has several advantages in optical performance comparing with a conventional on-axis telescope. However, in general, an off-axis telescope has a narrow field of view due to the linear astigmatism caused by the asymmetric structure. It was shown in the previous work that the linear astigmatism can be eliminated by properly configuring parameters in a confocal off-axis reflector system. Furthermore, the third order aberrations of a confocal off-axis telescope can be minimized by optimizing the shape of the mirrors. Despite many advantages, the confocal off-axis telescopes have been evaded because of difficulties of off-axis mirror fabrication, alignment process and unaccustomed off-axis baffle design. The baffle for the off-axis telescope should be designed considering that the effects of stray lights are different because of the asymmetry of off-axis system. In this poster, the design, manufacturing, and test for the baffle and housing of an off-axis telescope are presented.

• Korean Journal of Optics and Photonics
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• v.24 no.6
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• pp.338-341
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• 2013

Prothrombin Time (PT) is used as a measure of blood coagulation time. An optical analysis of the signal generating mechanism is described here for the reflection-type arrangement. Thromboplastin added into serum or whole blood initiates the coagulation process. We added a sufficient amount of magnetic particles into the sample before adding thromboplastin and subjected the mixture to a rotating magnetic field. The laser light gets reflected in a periodically modulated fashion with respect to the magnetic field rotation. Analysis of this decaying modulation could produce a reasonable coagulation time. We also introduce a simulation model to explain the signal generating mechanism using LightTools.$^{TM}$

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.94-100
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• 2016

A novel optical design for high resolution, large field of view (FOV) and multispectral remote sensing is presented. An f/7.3 Korsch and two f/17.9 Cook three-mirror optical systems are integrated by sharing the primary and secondary mirrors, bias of the FOV, decentering of the apertures and reasonable structure arrangement. The aperture stop of the Korsch system is located on the primary mirror, while those of the Cook systems are on the exit pupils. High resolution image with spectral coverage from visible to near-infrared (NIR) can be acquired through the Korsch system with a focal length of 14 m, while wide-field imaging is accomplished by the two Cook systems whose focal lengths are both 13.24 m. The full FOV is 4°×0.13°, a coverage width of 34.9 km at the altitude of 500 km can then be acquired by push-broom imaging. To facilitate controlling the stray light, the intermediate images and the real exit pupils are spatially available. After optimization, a near diffraction-limited performance and a compact optical package are achieved. The sharing of the on-axis primary and secondary mirrors reduces the cost of fabrication, test, and manufacture effectively. Besides, the two tertiary mirrors of the Cook systems possess the same parameters, further cutting down the cost.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1123-1123
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• 2001

In recent years, a miniature spectrometer has been extensively developed due to the marriage of fiber optics and semiconductor detector array. This type of miniature spectrometer has advantages of low price and robustness due to the capability of mass production and no moving parts are required such as lenses, mirrors and scanning monochromator. These systems are ideal for use in teaching labs, process monitoring and field analyses. A portable near infrared (NIR) system has been developed for qualitative and quantitative analysis. This system includes a tungsten halogen lamp for light source, a fiber optics connected a light source, and a sample module to the microspectrometer, The size of spectrometer can be as small as 2.5 cm x 1.5 cm x 0.1 cm. Wavelength ranges can be chosen as 360-800 nm, 800-1100 nm and 1100-1900 nm depending on the type of detector. The software consists of various tools for multivariate analysis and pattern recognition techniques. To evaluate the system, long and short-term stability, wavelength accuracy, and stray light have been investigated and compared with conventional scanning type NIR spectrometer. This developed system can be sufficiently used for quantitative and qualitative analysis for various samples such as agricultural product, herbal medicine, food, petroleum, and pharmaceuticals, etc.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1310-1311
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• 2011

본 논문에서는 신개념의 에너지 하베스팅 기술로서 전력선의 표유전계에너지 하베스팅을 제안하였고, 저전력 무선 센서노드에 전력공급이 가능함을 실험적으로 확인하였다. 전류가 흐르지 않는 무부하 상태의 220 V 전력선에 20 cm 길이의 알루미늄 포일을 감아서 하베스팅 할 때, 하베스터 회로의 접지가 220 V 전력선의 접지선에 연결되어 있는 경우, 수집 가능한 평균전류는 900 nA, 연구실 콘크리트 바닥에 접지되어 있을 경우, 700 nA의 평균전류를 얻을 수 있음을 확인하였다. 콘크리트 바닥에 접지되어 있는 하베스터 회로의 경우 220 V 전력선으로부터 접지선을 따로 빼 낼 필요가 없기 때문에 충분히 실용적이며 알루미늄 포일의 길이를 60 cm로 느리면 약 2분 만에 저전력 무선 센서노드 구동을 위해 필요한 에너지인 약 2 mJ 만큼 하베스팅이 가능하다. 본 기술을 적용하면 유비쿼터스 센서 네트워크의 전력을 공급할 수 있을 것으로 사료된다.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.99-104
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• 1999

The large scale industry needs high voltage converters. Therefore series connection of power semiconductor devices is necessary. It is important to prevent the overvoltage from being induced across a device above ratings by the proper voltage balancing in the field of IGBT series connection. In addition, the overvoltage induced by a stray inductance has to be limited in the high power circuit. This paper proposes a new gate control scheme which can balance the voltage properly and limit the overshoot by controlling the slope of collector voltage under the turn-off transient in the series connected IGBTs. The proposed gate control scheme which senses the collector voltage and controls the gate signal actively limits the overvoltage. The new series connected IGBT gate driver is made and its validity is verified by the experimental results in the series connected IGBT circuit.

• Journal of Forest and Environmental Science
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• v.34 no.1
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• pp.95-100
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• 2018

Rabies causes the highest mortality of all viral diseases in the world unless the victim has been protected either by active immunization or post-exposure immunoprophylaxis. Infected stray dogs, raccoons, skunks, foxes and bats are the demonstrated carriers of most cases of rabies. It is difficult to diagnose a rabid animal in the field unless characteristic clinical signs are evident. However, this study used a commercial fast check kit comprised of immunochromatographic test (ICT) strips (ICTS) to diagnose rabies infection in clinically suspected samples obtained from a wildebeest. A 10-year old male wildebeest (approximate weight, 150 kg) died at Bangabandhu Sheikh Mujib Safari (BSMS) Park, Cox's Bazar, Bangladesh with a clinical history of severe excitation and abundant oral secretions. A gross pathological examination revealed no specific lesions indicating any fatal diseases. The entire brain was collected within 6 hours of death, and the brain sample was tested using the ICT strips following the manufacturer's directions. The rabies viral antibody was detected within the brain stem and medulla of the brain tissue of the dead wildebeest.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.253-259
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• 2018

The Korea Convergence Society. Recently, as the 4th industrial revolution is rising, there are many changes in various field of industries. Among these industries, autonomous vehicles based on artificial intelligence, big data and internet of things is one of the most promising industry. Autonomous vehicle stray from classical car domain of manufacturers and suppliers, IT/Electronics suppliers and communication companies are widen their business area to autonomous vehicle technology. In this paper, we analysis the state of art of autonomous vehicle technology and development direction of industries/research institute. Finally, we discuss the social/economic effects of autonomous vehicle.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1546-1551
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• 2008

This paper is concerned with the problems of accurate losses segregation in capacitor-run single phase motor. Segregation of losses in single phase induction motor is more complicated than that in three phase induction motor, because of the backward magnetic field component in the motor. Generally there are two methods for losses segregation of single phase induction motor. The one is relatively complicated method based on parameter estimation of single phase induction motor. By the way, the other one is simplified method based on IEEE Standard 114. All of the methods for the experimental determination of single phase induction motor losses are studied in this paper. Since the IEEE Standard is not possible to be applied for all type of single phase induction motors, we modified that method to apply for losses segregation of capacitor-run single phase induction motor as unifying the method based on parameter estimation.

• Korean Journal of Veterinary Research
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• v.52 no.2
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• pp.75-82
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• 2012

We have developed and optimized a multiplex polymerase chain reaction (mPCR) for simultaneous detection of Brucella, Salmonella and Leptospira with high sensitivity and specificity. Three pairs of oligonucleotide primers were designed to specifically amplify the targeted genes of Salmonella, Leptospira and Brucella species with sizes of 521, 408 and 223 bp, respectively. The mPCR did not produce any nonspecific amplification products when tested against 15 related species of bacteria. The sensitivity of the mPCR was 100 fg for Brucella and 1 pg for both Salmonella and Leptospira species. In the field application, kidney, liver and spleen were collected from wild rats and stray cats and examined by mPCR. The high specificity and sensitivity of this mPCR assay provide a valuable tool for diagnosis and for the simultaneous and rapid detection of three zoonotic bacteria that cause disease in both humans and animals. Therefore, this assay could be a useful alternative to the conventional method of culture and single PCR for the detection of each pathogen.