• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.3
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• pp.104-110
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• 2001

In this study, the effect of physico-chemical variables on sludge conditioning was determined to enhance dewaterability of effluent produced from the thermophilic anaerobic digestion of food waste. The gas production rate and methane content during the anaerobic digestion of food waste were $1.1m^3/kg$ VS and 63%, respectively, and the biodegradability of volatile solids was 87.5%. The concentrations of CODcr, TKN and TP of effluent from digestor were 18,500mg/L, 2,800mg/L, and 582mg/L, respectively. At the jar test to screen the flocculant for the dewatering of effluent from digestor, $FeCl_3$ and strong cationic polymer were effective on making flocs in the effluent. The condition of flocculation of effluent were 500mg/L of $FeCl_3$ and 50-100 mg/L of strong cationic polymer, respectively. As the result of measuring of dewaterability potential of effluent to determine the mixing ratio between $FeCl_3$ and polymer by capillary suction time(SCT), optimum condition was 500mg/L of $FeCl_3$ and 80mg/L of strong cationic polymer.

• Applied Biological Chemistry
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• v.42 no.1
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• pp.58-62
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• 1999

Method to access qualities of brown sauce and optimize its cooking conditions was studied by sensory evaluation and response surface methodology. Cooks of an hotel, sauce experts, were selected as sensory panelists, and the brown sauce cooking conditions practically used in an hotel were adopted to prepare sauce samples for the sensory test. The cooking conditions were designed with two factors, i.e., one factor of roux contents with three levels and the other factor of cooking times with three levels, which were known as most important in sauce cooking. Sensory acceptance evaluation with intensity 7 grades was applied for several sauce attributes such as color, flavour, viscosity, taste and overall. Ability of each panel to perceive the differences between the brown sauces prepared under different cooking conditions was judged, and only data of the 9 panelists proved as reliable among the 12 panelists were reflected. The acceptances by different cooking conditions were found to be in the order of 11 > 9 > 13% roux contents and 8 > 9 > 7 hr cooking times. Response surface methodology was treated with second-order model on the sensory data and the optimum cooking conditions with the highest acceptances were $10.3{\sim}10.8%$ roux content and 8 hr cooking time.

• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.71-76
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• 2004

In order to investigate the Post-operative changes in scoliotic spine according to selection of fusion level a mathematical finite element model of King-Moe type II scoliotics spine system was developed. By utilizing this finite element scoliosis model surgical correction simulation procedures of pedicle fixation and derotation were simulated. In consequence of the calculation by changing the fusion Levels, postoperative changes like Cobb angle, apical vertebrae axial rotation (AVAR), thoracic kyphosis, and rib hump were Qualitatively analyzed. In the analysis of operative kinematics, the decrease or Cobb angle was most prominent in distraction than in deroation. Applying the rod derotation only was not effective in decrease of Cobb angle but just caused increase of At AR and rib hump. From the operative simulation, co-action or distraction and translation during rod insertion has major impact on Cobb angle decrease and maintenance of kyphosis. With rod rotation, Cobb angle decrease was obtained, but combined increase of AVAR and rib hump was simulation observed as well. The case of most extended instrumentation range with 60o rod rotation produced double decrease of Cobb angle, but the increase of rib hump and AYAR occurred corresponding1y. The optimum selection of fusion level was proved as one level less than inflection position of the thoracic spine curvature.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.10
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• pp.551-557
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• 2015

This study analyzes potentially hazardous sub-watersheds from non-point source pollution areas using an HSPF model. The watershed of the Juam dam reservoir was divided into 29 sub-watersheds, and the flow, BOD, TN and TP concentration for the Juam dam watershed were evaluated from 2009 to 2012 using a watershed model, with a warming period from 2009 to 2010. The results of the watershed model agreed well with the flow and water quality field measurements. The calculated average non-point source loadings were BOD of 8.8 and $9.1kg/day/km^2$ in 2011 and 2012, respectively; TN of 9.7 and $10.1kg/day/km^2$ in 2011 and 2012, respectively; and TP of 0.30 and $0.33kg/day/km^2$ in 2011 and 2012, respectively. The non-point source loading of the Bonghwa stream watershed was calculated, and predominantly assessed upstream of the Boseong river. Additionally, the Miryeok, Jangpyeong, Yuleo, Guam, Seokgyo, Mundeok, Incheon, and Bongnae stream watersheds, with extensive agricultural areas, were assessed to be potentially hazardous areas in terms of non-point source management. In this study, HSPF model was applied in order to aid in the selection of non-point source reduction facilities for the Juam dam watershed, where they were evaluated as to whether they would be applicable for non-point source management.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.1
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• pp.34-44
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• 2015

This study was initiated to remove free cyanide from wastewater using the process of photocatalytic oxidation. UV lamp has been extensively used as a light source in conventional photocatalytic oxidation, but numerous drawbacks of UV lamp have been raised so far. Thus, this study focused on evaluating the applicability of UV LED as an alternative light source to overcome the drawbacks of UV lamp. Furthermore, the effects of diverse operational parameters on the performance of process were investigated. The results demonstrated the applicability of UV LED as a substitute of UV lamp. Also, the results show that the performance of process was improved by the increase in the number of UV LEDs used. To acquire economic feasibility as well as high efficacy, however, it is required to determine the optimum number of UV LED prior to practical implementation of the process. Among the three types of photocatalysts (anatase, rutile, and Degussa P25) tested, the Degussa P25 showed the greatest performance, and it was proven that the process was not improved as much as the Degussa P25 through simple mixing of anatase and rutile without any pretreatment. In addition, the removal efficiency of free cyanide appeared to be increased with the decrease in the particle size of $TiO_2$ photocatalyst. Besides, the process was enhanced with injection of oxygen which is considered as a major electron acceptor in the photocatalytic oxidation.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.1
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• pp.40-49
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• 2017

In this study, we have made the annual total phosphorus (TP) mass balance diagrams for I wastewater treatment plant by utilizing the data of flow rate and TP of each process and tried to choose the optimum unit process empirically for phosphorus recovery. For the applicability evaluation, we have suggested several quantitative indices of flow rate, TP concentration, TP load and SS. Based on the analyses of TP mass balance, it became clear for reducing TP load of the wastewater treatment plant that it is efficient to recover phosphorus from the side stream in which the amount of flow rate is just 1/16, but TP concentration and load are 78 and 4.8 times larger than those of the influent of the plant. After the detailed applicability evaluation for the side stream, it could be concluded that the unit process of waste activated sludge thickener supernatant or dehydration filtrate are appropriate. Meanwhile, we did fundamental experiments utilizing the dewatering filtrate with TP concentration of 141.5 mg/L. After adjusting pH 10 and $Ca^{2+}$ concentration 250, 500, 1000 mg/L, it was stirred slowly. As a result, the $PO_4-P$ and TP removal efficiencies were above 95 percent; the results of the experiment imply the applicability of phosphorus recovery process in a wastewater treatment plant strongly.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.64-64
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• 2018

생물전환(Bioconversion)은 천연소재의 기능성을 증대시키기 위한 방안으로 많은 연구가 진행되고 있으며 다양한 산업에서도 활용되고 있어 유용미생물을 기반 차세대 기술로 각광받고 있다. 이러한 기술의 도입은 식품은 물론 의약품 및 화장품 산업에서도 활발히 사용되고 있으며, 특히 최근 기능성 제품에 대한 소비가 급증함에 따라 그 중요성이 높아지고 있다. 산초(Zanthoxylum schinfolium)는 limonene, citronellal, phellandrene 등의 다양한 유효물질을 함유하고 있으며 유효성분들로부터 유래되는 항산화 활성과 항암활성, 항균활성 등의 효능을 지니는 것으로 보고된바 있다. 본 연구의 생물전환 공정에 사용된 유산균들은 전통 발효식품으로 알려진 다양한 젓갈류로부터 분리하였으며, 16S rDNA 염기서열 분석을 통해 유전학적 특성을 확인하였다. 또한 확보된 유산균들을 사용하여 산초(전북 진안군) 분말의 발효공정을 수행하였으며, 산초의 최적 추출조건을 선정하고 추출물을 제조하여 생물전환 공정 전 후 활성의 변화추이를 관찰하였다. 추출물의 활성평가는 항산화 효능 및 유효성분 함량을 평가하기 위하여 DPPH radical scavenging activity와 total polyphenol 함량을 평가하고 세포주를 활용해 MTT assay, Nitric oxide(NO) 생성억제 효능을 확인하여 세포독성 및 항염증 활성을 확인하였다. 실험결과, 생물전환 공정에 사용할 유용 미생물을 확보하기 위한 실험을 통해 다양한 젓갈류에서 다양한 미생물을 확보할 수 있었으며 약 16종의 유산균을 분리하였다. 분리된 미생물을 사용하여 산초 분말의 생물전환 공정을 실시한 결과, 5종의 유용미생물 처리에서 무처리 대비 DPPH radical 소거능 및 polyphenol 함량이 유의적으로 증가됨을 확인할 수 있었다. 그 중 가장 높은 활성을 나타내는 균주를 16S rDNA 염기서열 분석을 통해 확인한 결과 Weissella confusa D1로 확인되었다. 선별 균주를 활용한 생물전환 공정 후 항산화 활성은 대조군 대비 약 120%의 활성을 나타냈으며, polyphenol의 함량은 약 126%로 증가하는 것을 확인할 수 있었다. 더 나아가 생물전환 공정 후 산초추출물의 세포독성은 처리전과 비교하여 월등히 감소하는 경향을 확인할 수 있었으며, 항염효능 또한 증가하는 경향을 나타내는 것이 확인되었다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.389-397
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• 2004

본 연구는 GIS를 이용하여 아파트 단지의 UHF대역의 전파장애에 대한 예측모델을 제시한다. 전파예측모델은 기지국 및 중계기 위치설계와 전파음영지역 결정 등 무선네트워크 서비스에 결정적으로 활용된다 기존의 전파예측모델은 한국지형요소나 3차원 공간기술이 반영되지 않고 외국지형기반의 2차원적인 접근으로 개발되어 있다. 특히 많은 사람이 거주하는 아파트단지에 대해서는 고려가 되어 있지 않은 실정이며, 마치 아파트 단지가 일반 건물로 취급되어 전파환경 요소로 분류되지 않은 상태이다. 그리고 전파관리자가 기존 전파 예측모델을 이용한 무선네트워크 설계 및 운용등에 있어 정확한 의사결정지원에 어려움이 많다. 본 연구는 이러한 한계와 문제점을 해결하기 위해서 아파트 단지의 전파에 대한 영향을 3차원 공간밀집, 건물높이, 전파의 전송방향에 대한 건물배치등 3가지 요소로 분류하고 GIS 도구로 그 요소들을 분석하였다. 그 결과로 상관과 회귀분석등 정량적인 방법으로 평가하여 아파트 전파예측모델(GARP)을 개발하여 다음의 결과를 얻었다. 첫째, 아파트 단지가 UHF 대역의 전파에 대한 영향은 전파진행방향성이 57%, 공간밀집이 30%, 건물높이가 13%의 순으로 나타났다. 둘째, 본 연구에서 개발된 아파트 모델은 기존 모델에 비해 평균 6.3dBm, 최소 2.15 ～ 최대 12.48dBm의 개선 효과가 있다. 셋째, 급속히 확산되는 도시 개발에 3차원 공간상에서 전파예측모델을 시뮬레이션하여 전파의 영향을 예측할 수 있으며, 대단지 아파트 건설과 전파환경영향평가의 기초정보 수집에 활용될 수 있다. 본 연구는 GARP모델과 GIS 가시권 분석기능을 이용하여 실제 지형공간상에서 전파경로 손실치를 도시화함으로써 전파관리자가 무선서비스지역 설계, 전파음영지역 판단, 최적 중계기와 기지국 위치 선정에 기여할 것으로 판단된다.하지 않은 지역과 서로 다른 분광특성을 나타내므로 별도의 Segment를 형성하게 된다. 따라서 임상도의 경계선으로부터 획득된 Super-Object의 분광반사 값과 그 안에서 형성된 Sub-Object의 분광반사값의 차이를 이용하여 임상도의 갱신을 위한 변화지역을 탐지하였다.라서 획득한 시추코아에 대해서도 각 연구기관이 전 구간에 대해 동일하게 25%의 소유권을 가지고 있다. ？스굴 시추사업은 2008년까지 수행될 계획이며, 시추작업은 2005년까지 완료될 계획이다. 연구 진행과 관련하여, 공동연구의 명분을 높이고 분석의 효율성을 높이기 위해서 시료채취 및 기초자료 획득은 4개국의 연구원이 모여 공동으로 수행한 후의 결과물을 서로 공유하고, 자세한 전문분야 연구는 각 국의 대표기관이 독립적으로 수행하는 방식을 택하였다 ？스굴에 대한 제1차 시추작업은 2004년 3월 말에 실시하였다. 시추작업 결과, 약 80m의 시추 코아가 성공적으로 회수되어 현재 러시아 이르쿠츠크 지구화학연구소에 보관중이다. 이 시추코아는 2004년 8월 중순경에 4개국 연구팀원들에 의해 공동으로 기재된 후에 분할될 계획이다. 분할된 시료는 국내로 운반되어 다양한 전문분야별 연구에 이용될 것이다. 한편, 제2차 시추작업은 2004년 12월에서 2005년 2월 사이에 실시될 계획이다. 수백만년에 이르는 장기간에 걸쳐 지구환경변화 기록이 보존되어 있는 ？스굴호에 대한 시추사업은 후기 신생대 동안 유라시아 대륙 중부에서 일어난 지구환경 및 기후변화를 이해함과 동시에 이러한 변화가 육상생태계 및 지표지질환경에 미친 영향을 이해하는데 크게 기여할 것이다.lieve in safety with Radioactivity wastes control for harmony with Environment.d by the experiments under vari

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.509-514
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• 2020

The conventional TTS system consists of several modules, including text preprocessing, parsing analysis, grapheme-to-phoneme conversion, boundary analysis, prosody control, acoustic feature generation by acoustic model, and synthesized speech generation. But TTS system with deep learning is composed of Text2Mel process that generates spectrogram from text, and vocoder that synthesizes speech signals from spectrogram. In this paper, for the optimal Korean TTS system construction we apply Tacotron2 to Tex2Mel process, and as a vocoder we introduce the methods such as WaveNet, WaveRNN, and WaveGlow, and implement them to verify and compare their performance. Experimental results show that WaveNet has the highest MOS and the trained model is hundreds of megabytes in size, but the synthesis time is about 50 times the real time. WaveRNN shows MOS performance similar to that of WaveNet and the model size is several tens of megabytes, but this method also cannot be processed in real time. WaveGlow can handle real-time processing, but the model is several GB in size and MOS is the worst of the three vocoders. From the results of this study, the reference criteria for selecting the appropriate method according to the hardware environment in the field of applying the TTS system are presented in this paper.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.55-62
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• 2001

With a spread of BGA, CSP and fine pitch devices, the need of flatter surface finish in bare board is becoming more critical in solderability. The electroless Ni/Au plating has a solution of these needs and also has being spread to apply to surface finish for bare board in many electronic goods. But, the electroless Ni/Au plating had several issues such as Ni oxidation and phosphorous contents. Before this study, we studied on the effect of BGA solderability in electroless Ni/Au plating and chose some major factors such as the oxidation property of NiP plating and warpage of board. Firstly, we made test board with various plating conditions and improved the plating property through the improvement of NiP oxidation reducing P content. Also, we minimized the warpage of board with the improvement of inner layer structure and the analysis of warpage. For the evaluation of solderability, we analyzed the warpage of board and the plating property after mounting BGA on the board with optimizing conditions. The solder joint of BGA is investigated by SEM(Scanning Electronic Microscope) and OM(Optical Microscope). The composition of joint is used by EDS(Energy Dispersive Spectroscopy). We analyzed the fracture strength and mode by ball shear teser.