The site coefficients in the common requirements for seismic design codes, which were promulgated in 2017, were reevaluated and the standard design spectrum for soil sites were newly proposed in order to ensure the consistency of the standard design spectra for rock and soil sites specified in the common requirements. Using the 55 ground motions from domestic and overseas intraplate earthquakes, which were used to derive the standard design spectrum for rock sites, as rock outcropping motions, site response analyses of Korean soil were performed and its ground-motion-amplification was characterized. Then, the site coefficients for soil sites were reevaluated. Compared with the existing site coefficients, the newly proposed short-period site coefficient Fa increased and the long-period site coefficient Fv decreased overall. A new standard design spectrum for soil sites was proposed using the reevaluated site coefficients. When compared with the existing design spectrum, it could be seen that the proposed site coefficients and the standard design spectrum for soil sites were reasonably derived. They reflected the short-period characteristics of earthquake and soil in Korea.

Capacitive deionization (CDI) process is an emerging process for water desalination. Recently, there has been a major development of architectures in CDI cells using carbon flow electrodes with membrane, called flow-electrode capacitive deionization (FCDI). In FCDI, the advantage is continuous desalination due to the carbon flow electrodes. Numerous research groups dedicated to develop the FCDI process, however, a clear pre-treatment of carbon flow electrodes was not suggested. Study herein, present a clear understanding of effects of pre-treatment of activated carbon based on sonication in the carbon flow electrodes for the basics results with respect to adsorption performance.

Forward Osmosis process has no, as yet, reliable method to predict fouling. This study utilized the concept of fouling reversibility to develop the index. The osmotically-driven reversibility index, denoted as ORI, was acquired by measuring the flux recovery after physical cleaning cycle and the protocols of ORI were developed systematically by considering all the critical factors of FO process. The applicability of ORI was examined by investigating FO process when treating secondary effluents from various full-scale wastewater treatment plants. The results demonstrated that the normalized final flux by fouling in FO was closely correlated to the ORI measurements with high statistical reliability. The ORI has proven to be useful evaluation parameter for continuous operation and determining cleaning cycles of FO process.

본 연구는 느타리버섯 수확후배지를 배지자원으로 재사용하기 위하여 미생물처리에 의한 수확후 배지의 총질소함량 증진효과를 조사하였다. Bacillus sp. GM20-4 와 Rhodobacter sphaeroides(RS) 배양액 30%를 함께 접종하여 5일간 상온에서 배양 시 총질소 함량이 가장 크게 증가하였다. 농가의 수확후배지 조성에 따른 GM20-4와 RS 처리에 의한 T-N함량 변화를 조사하기 위하여 경기 지역 버섯재배농가 세 곳의 수확후배지(spent mushroom substrates, SMS A, B, C)를 수집하여 GM20-4 와 RS 배양액 30%를 처리한 결과, 무처리구에 비해 건조 SMS B 에서 T-N함량이 20%p로 가장 크게 증가하였고, 건조 SMS A는 17%, C는 12% 증가하였다. 반면에 생수확후 배지에서는 미생물 처리에 의한 T-N 함량 증가 효과가 크지 않았다. 또한 아미노산 조성별 함량 변화는 건조된 SMS A, B, C 모두 GM20-4와 RS 처리로 aspatic acid와 glutamic acid가 상대적으로 높게 증가한 결과를 보였고, 특히 건조 SMS B의 처리구에서 두 아미노산의 함량이 무처리구보다 2.9배 증가를 보임으로서 미생물처리가 수확후배지의 총질소 및 아미노산 함량의 증진효과를 확인하였다.

This study is conducted as a preliminary research to verify the feasibility of Ti-based Oxide dispersion strengthened (ODS) alloy. Pure-Ti powder is mixed with Y2O3 powder and subsequently, mechanically alloyed at -150oC. The Ti-based ODS powder is hot-isostatically pressed and subsequently hot-rolled for recrystallization. The microstructure consists of elongated grains and Y excess fine particles. The oxide particle size is larger than that of the typical Febased ODS steel. Tensile test shows that the tensile ductility is approximately 25%, while the strength is significantly higher than that of pure Ti. The high-temperature hardness of the Ti-ODS alloy is also significantly higher than that of pure Ti at all temperatures, while being lower than that of Ti-6Al-4V. The dimple structure is well developed, and no evidence of cleavage fracture surface is observed in the fracture surface of the tensile specimen.

The microstructure and mechanical characteristics of SUS630 specimens fabricated using the direct energy deposition (DED) process are investigated. In DED, several process parameters such as laser scan speed, chamber gas flow, powder carrier gas flow, and powder feed rate are kept fixed; the laser power is changed as 150 W, 180 W, and 210 W. As the laser power increases, the surface becomes smooth, the thickness uniformity improves, and the size and number of pores decreases. With the increase in laser power, the hardness deviation decreases and the average hardness increases. The microstructure of the material is columnar; pores are formed preferentially along the columnar interface. The lath-martensite phase governs the overall microstructure. The volumetric fraction of the retained austenite phase is measured to increase with the increase of laser input power.

본 연구에서는 평균온도 상승에 따른 출수기변화, 수량구성 요소 및 수량, 출수기건물중 및 식물체 질소함량 변화를 평가 한 결과는 다음과 같았다. 1. 생육기 평균온도 1oC 상승 시 밀의 출수기는 약 2.8일 단축된 것으로 판단되었다. 2. 평균온도 상승 시 수량구성요소와 수량이 악화되었는데, 주로 면적당수수 감소에 의해 면적당립수와 수량이 감소한 것으로 판단되었다. 3. 1수립수는 11월 7일 파종 시 고온조건에서 감소하였으나 11월 17일 파종 시 고온조건에서 감소하지 않았다. 4. 천립중은 출수 후 30일간 평균온도 1oC 당 약 2.1g씩 감소하였다. 5. 평균온도 상승 시 출수기 건물중은 감소하지 않았으나, 출수기 면적당경수는 감소한 것으로 판단되었다. 6. 고온처리 시 식물체 질소흡수량이 감소하여 면적당립수가 감소한 것으로 판단되었다.

잎새버섯을 병재배 새로운 소득 품목으로 개발하고자 적정 발이방법을 구명하기 위한 연구결과는 다음과 같다. 발이는 모든 처리구에서 6일째 개시가 되었으나, T7(균긁기후 역상)은 9일로 다른 처리보다 3일 늦었다. 발이율은 T3(페트리디쉬)과 T7이 98.9%로 가장 높고, 전체 재배기간은 T7이 51일로 다른 처리구의 46~47일보다 3일 늦은 것으로 나타났다. 수량성은 T3과 T7이 각각 110g과 112g으로 우수하였으나, T7의 방법이 자실체의 발생도 균일하고, 품질도 우수하여(장단비 0.89) 잎새버섯 병재배에 적합한 발이방법으로 판단되었다.

표고 재배용 액체종균 배지조성은 대두박분 배지에 입도가 850 μm이하인 참나무분 0.3% 첨가 시 균사체 건중량이 457 mg으로 다소 높았으며, Laccase 활성도는 참나무분 첨가율별 대두박분 배지에 큰 차이가 없었으나 Cellulase 활성도는 CMC Agar Plate에서 26.4 mm로서 참나무분 첨가율별 대두박분 액체종균 처리구중에서 가장 우수하였다. 액체종균의 통기량이 증가할수록 이산화탄소 발생량이 증가하여 배양 7일째 최대치를 나타내었으며 균사체 건중량은 10일째 3.0g/l로 가장 우수한 것으로 나타났다. 통기량이 증가할수록 이산화탄소 발생량, 균사체 건중량도 증가하였으며 0.6vvm 처리시 배지 증발율이 32%, 균사체 건중량이 3.5g/l로서 우수하였다. 선발된 액체종균을 톱밥 종균과 생산성 비교를 위하여 톱밥재배 봉지배지에 시험한 결과, 액체종균의 생육기간이 톱밥종균에 비해 1일 지연되었으나, 봉지당 유효 개체수와 수량에는 유의적인 차이가 없는 것으로 나타났다.

느타리버섯 수확후 배지를 이용하여 표고 톱밥배지로 활용하기 위한 연구 수행결과 다음과 같다. 느타리버섯 수확후 배지를 톱밥 첨가량의 20~50%로 4처리로 혼합하여 분석한 결과 C/N은 62~76으로 나타났다. 느타리버섯 수확후 배지 첨가구는 대조구에 비해 질소와 폴리페놀 함량은 상대적으로 높고, 과당과 유기산 함량은 낮은 경향이었다. 특히, 미강이 첨가되지 않은 50% 처리구는 과당, 유기산 함량이 현저하게 낮았다. 초발이기간은 20, 25%가 7일로 대조구와 같았으나 30%와 50%는 각각 6일, 11일로 대조에 비해 각각 1, 4일 지연되었다. 표고버섯 3주기 수량은 20% 처리구가 268.7 g으로 대조와 비슷하였으나 첨가수준이 높을수록 감소하여 특히, 50% 첨가구에서는 버섯 발생이 거의 이루어지지 않았다. 따라서 느타리버섯 수확후 배지를 표고 배지로 이용하기 위해서는 톱밥 첨가량의 20% 수준이 바람직할 것으로 생각된다.

In recent years, imbalanced data is one of the most important and frequent issue for quality control in industrial field. As an example, defect rate has been drastically reduced thanks to highly developed technology and quality management, so that only few defective data can be obtained from production process. Therefore, quality classification should be performed under the condition that one class (defective dataset) is even smaller than the other class (good dataset). However, traditional multi-class classification methods are not appropriate to deal with such an imbalanced dataset, since they classify data from the difference between one class and the others that can hardly be found in imbalanced datasets. Thus, one-class classification that thoroughly learns patterns of target class is more suitable for imbalanced dataset since it only focuses on data in a target class. So far, several one-class classification methods such as one-class support vector machine, neural network and decision tree there have been suggested. One-class support vector machine and neural network can guarantee good classification rate, and decision tree can provide a set of rules that can be clearly interpreted. However, the classifiers obtained from the former two methods consist of complex mathematical functions and cannot be easily understood by users. In case of decision tree, the criterion for rule generation is ambiguous. Therefore, as an alternative, a new one-class classifier using hyper-rectangles was proposed, which performs precise classification compared to other methods and generates rules clearly understood by users as well. In this paper, we suggest an approach for improving the limitations of those previous one-class classification algorithms. Specifically, the suggested approach produces more improved one-class classifier using hyper-rectangles generated by using Gaussian function. The performance of the suggested algorithm is verified by a numerical experiment, which uses several datasets in UCI machine learning repository.

Post-earthquake risk assessment technique in Korea is developed in 2013 by National Disaster Management Research Institute, at the same time, related manual and standard regulation is distributed to every local government by National Emergency Management Agency. The objectives of this research are to investigate and evaluate the post-earthquake risk assessment of 9.12 Earthquake (M5.8, Gyeongju City, 2016) and 11.15 Earthquake (M5.4, Pohang City, 2017). To suggest and improve the assessment process of post-earthquake risk, first post-earthquake risk assessment method of advanced foreign countries including US, New Zealand and Japan are compared, and post-earthquake evaluation activities in 9.12 Earthquake and 11.15 Earthquake are analyzed. From the results, it is needed to expand the adapted building and structure types and strengthen the earthquake disaster response capacity of local government.

On November 15, 2017, Pohang earthquake occurred. Its local magnitude was announced to be ML=5.4 by Korea Meteorological Administration (KMA). Ground motion data recorded at KMA stations were obtained from their data bases. From the data, horizontal and vertical response spectra, and V/H ratio were calculated. The horizontal spectra were defined as GMRotI50 spectra. From the statistical analysis of the GMRotI50 spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. Applying the same procedure, the shape and transition periods of vertical spectrum were obtained. These results were compared with the Korean standard design spectra, which were developed from domestic and overseas intra-plate earthquake records, and Gyeongju earthquake response spectra. The response spectra of Pohang earthquake were found to be almost identical with the newly proposed design spectra. Even the V/H ratios showed good agreement. These results confirmed that the method adopted when developing the standard design spectra were valid and the developed design spectra were reliable.

The purpose of this study was to analyze some parameters’ effects on buckling behavior of Sinusoidal Corrugated Web using finite element analysis program. Studying buckling behavior is one of the most important things to design sinusoidal corrugated web girders and predict the shear performance. In this paper, Four parameters of Sinusoidal Corrugated Web, which are thickness( ), height( ), wave height( ) and wave length( ), were selected for buckling behavior analysis. Via buckling analysis, it is shown that  ,  and  have influence on shear buckling stress, Initial stiffness and reduced strength after buckling.

백령버섯 병재배용 배지 주재료는 콘코브 배지보다는 미루나무톱밥 배지 처리구에서 발이 및 생육특성이 가장 양호하였으며, 배지 영양원으로는 면실피, 면실박, 밀기울, 옥수수분, 미강 등이 적합하였고, 배지 혼합 비율은 58% 이내 범위에서 재료별로 질소함량을 고려하여 가감 사용하는 것이 적당하였으며, T-N 함량이 높은 면실박 사용량은 20% 수준으로 조절할 필요가 있었다. 또한, 배지 첨가제는 탄산칼슘 처리가 소석회 처리보다 양호하였으며, 무처리구의 경우 갓과 대의 탄력성은 감소하고 경도는 증가되는 경향을 보였다. 따라서, 백령버섯 병재배용 최적배지는 미루나무톱밥+면실피+면실박+밀기울+옥수수분+탄산칼슘이 40:20:20:15:3:2의 혼합 비율로 조성되는 처리구였다.

In this study, we develop and propose damping correction factors for the Korean standard design spectra. The newly proposed Korean standard design spectra has been given only for 5% damping ratio. But in practice, engineers need design spectra for damping values other than 5%. To obtain design spectra for various damping values from the standard spectra, damping correction factors are derived. These factors modify the shape of design spectra in accordance with the damping ratio. Response spectra for various damping values are calculated from the earthquake records that had been used to calculate standard design spectra. They consist of 55 records from 18 earthquakes occurred in overseas intraplate regions and Korea. The regressed spectra for the damping values ranging from 0.5% to 50% are compared with standard spectra at three regions acceleration, velocity and displacement sensitive regions. The regression analysis of these data rendered formula for damping correction factors. Finally, a single formula for damping correction factors is recommended that is valid for both horizontal and vertical design spectra and that is applicable to the entire range of periods. One thing to note that recommended damping correction factors is valid for the design spectrum of the rock grounds because the design spectra was developed based on the earthquake records of the rock ground.

전통적인 FRP 선체 제작에는 mould가 요구되며, mould의 높은 제작비용은 FRP 선박 제작자에게 비용부담을 주고 있다. 이를 극복하기 위한 방안으로 강선 건조에서 사용되는 블록 혹은 모듈 방식의 제작기법에 착안한 modular construction 방안이 제시되었다. 이 제작방안을 FRP 선체에 효율적으로 적용하기 위해서는 설계 및 제작 측면에서 간략하면서도 구조적 안정성을 갖는 접합 이음부 개발이 이루어져야 한다. 따라서, 본 논문에서는 모듈방식의 FRP 선체 제작을 위해 moulding-in 개념을 기반으로 한 경제적인 접합 이음부 개발에 관한 연구를 수행하였다. FRP 샌드위치 판을 대상으로 step, scarf-step 그리고 scarf 이음부 형상을 갖는 moulded-in을 수지주입식진공성형 공정에 도입하여 성공적으로 접합된 FRP 샌드위치판 을 제작하였다. 이에 대해 구조적 안정성 평가를 목적으로 인장 및 4점 굽힘 시험 그리고 유한요소해석을 수행하였다. 시험과 해석결과에 대한 비교 연구를 통해 본 연구에서 개발된 접합 이음 내용이 모듈방식의 FRP 선체 제작에 적용 가능함을 확인할 수 있었다.