• Clean Technology
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• v.4 no.1
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• pp.6-23
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• 1998

Recently, semiconductor industry has grown rapidly because of the large demand for electronic devices and equipment. The semiconductor industries have also played an important role on the economic growth in Korea. As the environmental regulations become strict, the proper environmental management and the well-developed waste minimization technologies in semiconductor industries are two of urgent problems to be solved. The semiconductor manufacturing process consists of a series of continuous chemical processes, such as cleaning, oxidation, diffusion, photolithography, etching and film deposition. During the processes, various environmentally hazardous wastes are produced. The wastes may be classified as wastewater, gaseous pollutants, and solid wastes. For waste minimization, the substitution of raw materials and process optimization techniques are used, while the selective destruction technologies of toxic chemicals contained in the wastes have been reported. Also, new technologies have been developed for source reduction and waste reduction, such as reduction of toxic chemical use and substitution of hazardous liquids with gaseous reactants or solvent.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.87.2-87.2
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• 2012

고출력 반도체 레이저 다이오드는 발진 파장 및 광 출력에 따라 다양한 분야에 응용되고 있으며, 특히 발진파장이 808 nm 및 1470 nm 인 고출력 레이저 다이오드의 경우 재료가공, 펌핑용 광원 (DPSSL, 광섬유 레이저), 의료, 피부미용 (점 제거), 레이저 다이오드 디스플레이 등 가장 다양한 응용분야를 가진 광원 중의 하나라고 할 수 있다. 일례로 재료가공의 경우, 레이저 용접, 레이저 인쇄, 하드디스크의 레이저 텍스쳐링 등 그 응용분야는 무수히 많으며, 최근에는 미래 성장동력 사업의 하나로 중요한 이슈가 되는 태양전지에서 에지 분리 (edge isolation), ID 마킹, 레이저 솔더링 등에서 필수불가결한 광원으로 각광받고 있다. 808 nm 대역 In(Ga)AlAs quantum dots laser diode (QDLD) 성장을 위하여 In(Ga)AlAs QD active 와 In(Ga)AlAs QD LD 성장으로 크게 분류하여 여러 가지 test 실험을 수행하였다. 우선 In(Ga)AlAs QD LD 성장에 앞서 high power LD에 적용 가능한 GaAs/AlGaAs quantum well의 성장 및 전기 측정을 수행하여 그 가능성을 보았다. In(Ga)AlAs QD active layer의 효과적인 실험 조건 조절을 위해 QD layer는 sequential mithod (ex. n x (InGaAlAs t sec + InAs t sec + As 10 sec)를 사용하였다. In(Ga)AlAs QD active layer는 성장 온도, 각 sequence 별 시간, 각 source 양, barrier 두께 조절 및 타입변형, Arsenic flux 등의 조건을 조절하여 실험하였다. 또한 위에서 선택된 몇 가지 active layer 를 이용하여 In(Ga)AlAs QD LD 성장 조건 변화를 시도하였다.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.539-550
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• 2014

Purpose: This research was designed to figure out if there are changes based on types of vergence fixation disparity curve after optical correction and vision training to for people with steep slope of forced vergence fixation disparity curve and symptoms. Methods: For 30 subjects out of 91 subjects, who have steep slopes of fixation disparity curve examined with Wesson Fixation Disparity Card and symptoms about steep slope of fixation disparity curve, proper vision training was offered for 5 weeks. Results: After Vision training for 30 people with the symptoms of type I, II, III, IV for 5 weeks, slope of fixation disparity curve was significantly changed (p=0.013), and the results of binocular vision test and subjective symptoms were also significantly improved. Conclusions: Vision training can not only affect the change of fixation disparity curve, but also relieve the symptoms. Fixation disparity curve has lots of visual function information of the subject and can be suggested as a guideline for prescribing.

• Journal of Biomedical Engineering Research
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• v.20 no.3
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• pp.291-297
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• 1999

Source consislency filtering (SCF) is very effective at removing nOIse when only one or a few leads among multi-lead ECG signals are contaminated. When the noise at one or only a few leads are statistically uncorrelated with signals at other leads, SCF seleclIvely removes the noise with a neglIgIble amount of distortion in the original signal waveform. In order to enhance the understanding of this new method, we describe the lheory and implementational details of SCF in this paper. Numerical implementation and test results of SCF on a multi-lead ECG dalabase show that SCF is a new kind of adaptive filters utilizmg spatial as well as temporal information in multi-c.hannel signals origmatmg from a single source. We also describe the limitations and future improvements in using SCF.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.5
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• pp.312-315
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• 2012

In this study, the model which can predict the quality of effluent has been implemented through multiple regression analysis to use operation data of a sewage treatment plant, to which a media process is applied. Multiple regression analysis were carried out by cases according to variable selection method, removal of outliers and log transformation of variables, with using data of one year of 2011. By reviewing the results of predictable models, the accuracy of prediction for $COD_{Mn}$ of treated water of secondary clarifiers was over 0.87 and for T-N was over 0.81. Using this model, it is expected to set the range of operating conditions that do not exceed the standards of effluent quality. In conclusion, the proper guidance on the effluent quality and energy costs within the operating range is expected to be provided to operators.

• Restorative Dentistry and Endodontics
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• v.32 no.6
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• pp.483-490
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• 2007

This report describes clinical cases of a palato-gingival groove on a maxillary lateral incisor with associated localized periodontal disease and pulp necrosis. The tooth of the first case was extracted because of severe bone destruction. The palato-gingival groove of the second case was eliminated using a round bur, and the resulting defect was filled with synthetic graft and covered by an absorbable membrane. Both diagnosis and treatment of palato-gingival groove were very difficult and usually extraction of the involved tooth is the treatment of choice. but combined endodontic-peri-odontic treatment allowed the tooth to be saved.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.4
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• pp.15-23
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• 2004

In order to utilize remote sensed images effectively, it is necessary to correct geometric distortion. Geometric correction is a critical step to remove geometric distortions in satellite images. For geometric correction, Ground Control Points (GCPs) have to be chosen carefully to guarantee the quality of geocoded satellite images, digital maps, GPS surveying or other data. Traditional approach to geometric correction used GCPs requires substantial human operations. Also that is necessary much time and manpower. In this paper, we presented an on-line automatic geometric correction by constructing GCP Chip database. The Proposed on-line automatic geometric correction system is consists of four part. Input image, control the GCP Chip, revision of selected GCP, and output setting part. In conclusion, developed system reduced the processing time and energy for tedious manual geometric correction and promoted usage of Landsat imagery.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.2
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• pp.89-98
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• 2004

In this paper, we implement a digital holographic security card system that combines digital holographic memory using random phase encoded reference beams with electrical biometrics. Digitally encoded data including a document, a picture of face, and a fingerprint are recorded by multiplexing of holographic memory. A random phase mask encoding reference beams are used as a decoded key to protect illegal counterfeit. As a result, we can achieve a raw BER of 3.6${\times}$10-4 and shift selectivity of 4${\mu}{\textrm}{m}$ using the 2D random phase mask. Also, we develop a recording pattern and image processing which are suitable for a low cost reader without a position sensing photo-detector for real time data extraction and remove danger of fraud from unauthorized person by comparing the reconstructed holographic data with the live fingerprint data.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.10
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• pp.103-112
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• 1999

Genetic algorithm, which uses principles of natural selection and population genetics, is an efficient method to find out an optimal solution. In conventional genetic algorithms, however, the size of gene pool needs to be increased to insure a convergency. Therefore, many memory spaces and much computation time were needed. Also, since child chromosomes were generated by chromosome crossover and gene mutation, the algorithms have a complex structure. Thus, in this paper, a compact stereo matching algorithm using a population-based incremental learning based on probability vector is proposed to reduce these problems. The PBIL method is modified for matching environment. Since th proposed algorithm uses a probability vector and eliminates gene pool, chromosome crossover, and gene mutation, the matching algorithm is simple and the computation load is considerably reduced. Even though the characteristics of images are changed, stable outputs are obtained without the modification of the matching algorithm.

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.556-562
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• 2000

The determination of chlorite ion by flow injection analysis(FIA) with iodometric UV detection were investigated. Under rather acidic condition, chlorite ion react with iodide ion to form iodine and itself is reduced to chloride ion. The chlorite ion was determined indirectly by measuring absorbance of yellow colored iodine at 370 nm. The lengths of the mixing coil and the reaction coil, the pH of the acid stream, the concentration of the iodide ion, the injection loop volume, temperature, and flowrate were optimized as parameters for selectively determining a sort of inorganic disinfection by-product, chlorite ion by using FIA-UV detection setup. Masking agents for removing oxidants or interferences from the prepared water were tested. Independent calibration curve presented linear range of 0.002-0.2 mg/L for chlorite ion with a correlation coefficient of 0.999 or better. The limit of detection(LOD) was 0.18 ${\mu}g/L$ for chlorite ion.