• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.237-240
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• 2006

Almost 30 years have been passed since the first nuclear power plant was operated in Korea. Many studies have been actively conducted from the early 1990's in order to develop the deterioration management system for concrete structures in NPPs(Nuclear Power Plants) accordingly. Base on these studies, a systematic deterioration management program has developed and operated since 1997. According to this program, systematic inspections to provide database and evaluation were periodically performed (every overhaul at intervals of $12{\sim}18$ month and every five years). Accumulated deterioration database was usefully utilized for the NPP PSR (Periodic Safety Review). In this paper, the long-term durability and integrity of Kori 1,2 NPP concrete structures which are the oldest ones in Korea were evaluated based on the precise inspection database and regulatory inspection results including compressive strength, depth of carbonation, amount of chlorination and spontaneous potential of reinforcing bar, etc. It was noted that Kori 1,2 NPP structures have not any serious durability problems.

• 대한기계학회논문집
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• 제12권5호
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• pp.1035-1042
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• 1988

본 연구에서는 단순절삭의 특성과 관련된 신호처리 방법을 검토하고, 선삭의 경우와 달리 제기되는 문제점중의 하나인 센서의 부착위치를 예비실험을 통하여 결정 하며, 공구마멸의 진전에 따른 AE신호의 특성변화를 조사하여 공구마멸 자동감지의 기 초가 되는 공구마멸의 점진적 증가에 따른 AE신호의 특성변화를 관찰하고자 한다. 특히 절삭조건 즉 이송량, 절석깊이, 절삭속도, 그리고 정착된 인서트의 수가 AE신호 의 특성에 미치는 영향을 각각 조사하여 절삭조건의 변화에 따른 AE신호의 변화경향을 살펴보고자 한다.

• Journal of Information Science Theory and Practice
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• 제3권2호
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• pp.16-30
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• 2015

The term megajournal is used to describe publication platforms, like PLOS ONE, that claim to incorporate peer review processes and web technologies that allow fast review and publishing. These platforms also publish without the constraints of periodic issues and instead publish daily. We conducted a yearlong bibliometric profile of a sample of articles published in the first several months after the launch of PeerJ, a peer reviewed, open access publishing platform in the medical and biological sciences. The profile included a study of author characteristics, peer review characteristics, usage and social metrics, and a citation analysis. We found that about 43% of the articles are collaborated on by authors from different nations. Publication delay averaged 68 days, based on the median. Almost 74% of the articles were coauthored by males and females, but less than a third were first authored by females. Usage and social metrics tended to be high after publication but declined sharply over the course of a year. Citations increased as social metrics declined. Google Scholar and Scopus citation counts were highly correlated after the first year of data collection (Spearman rho = 0.86). An analysis of reference lists indicated that articles tended to include unique journal titles. The purpose of the study is not to generalize to other journals but to chart the origin of PeerJ in order to compare to future analyses of other megajournals, which may play increasingly substantial roles in science communication.

• Membrane and Water Treatment
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• 제10권2호
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• pp.155-163
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• 2019

The roles of polypropylene (PP) beads and pH on membrane fouling and treatment efficiency were investigated in a hybrid advanced water treatment process of tubular carbon fiber membranes (ultrafiltration (UF) or microfiltration (MF)) and PP beads. The synthetic feed including humic acid and kaolin flowed inside the membrane, and the permeated contacted the PP beads fluidized in the space between the membrane and the module with UV irradiation and periodic water back-flushing. In the hybrid process of UF ($0.05{\mu}m$) and PP beads, final resistance of membrane fouling ($R_f$) after 180 min increased as PP beads increased. The turbidity treatment efficiency was the maximum at 30 g/L; however, that of dissolved organic matters (DOM) showed the highest at PP beads 50 g/L. The $R_f$ strengthened as pH of feed increased. It means that the membrane fouling could be inhibited at low alkali condition. The treatment efficiency of turbidity was almost constant independent of pH; however, that of DOM showed the maximum at pH 5. For MF ($0.1{\mu}m$), the final $R_f$ was the minimum at PP beads 40 g/L. The treatment efficiencies of turbidity and DOM were the maximum at PP beads 10 g/L.

• 지질공학
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• 제30권4호
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• pp.423-433
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• 2020

Direct current (DC) electric fields have been used for electro-osmotic dewatering. Under DC conditions, however, the electrical contact resistance between the electrode and the dewatering material increases considerably during the process of dewatering. Such a circumstance hinders the continuation of effective electro-osmotic dewatering. To reduce this hindrance, an applied pulse electric field with periodic reversals of the electrode polarity should improve electro-osmotic dewatering. In this study, electro-osmotic dewatering under pulse conditions was experimentally investigated for electrode polarity reversals. During the dewatering process, the pulse electric field was able to reduce the hindrance caused by the DC, resulting in an increased final dewatered amount relative to that under a DC electric field. For a constant applied voltage, the reversed polarity condition, under which the electric current passing through the material was almost unchanged with time, yielded the maximum final dewatered amount. This technique can be used to enhance drainage from a water storage facility during a period of extreme drought and the seawater desalination plants using reverse osmosis in drought stricken coastal regions.

• 대한수학회보
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• 제60권1호
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• pp.1-22
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• 2023

Let L(s, χ) be the Dirichlet L-series associated with an f-periodic complex function χ. Let P(X) ∈ ℂ[X]. We give an expression for ∑^f_n=1 χ(n)P(n) as a linear combination of the L(-n, χ)'s for 0 ≤ n < deg P(X). We deduce some consequences pertaining to the Chowla hypothesis implying that L(s, χ) > 0 for s > 0 for real Dirichlet characters χ. To date no extended numerical computation on this hypothesis is available. In fact by a result of R. C. Baker and H. L. Montgomery we know that it does not hold for almost all fundamental discriminants. Our present numerical computation shows that surprisingly it holds true for at least 65% of the real, even and primitive Dirichlet characters of conductors less than 10⁶. We also show that a generalized Chowla hypothesis holds true for at least 72% of the real, even and primitive Dirichlet characters of conductors less than 10⁶. Since checking this generalized Chowla's hypothesis is easy to program and relies only on exact computation with rational integers, we do think that it should be part of any numerical computation verifying that L(s, χ) > 0 for s > 0 for real Dirichlet characters χ. To date, this verification for real, even and primitive Dirichlet characters has been done only for conductors less than 2·10⁵.

• 대한수의학회지
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• 제29권4호
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• pp.445-455
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• 1989

The proteins of the ruminant erythrocyte membranes were analysed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, and their relations to the slow erythrocyte sedimentation rate(ESR) of the ruminants were investigated by treating the erythrocytes with proteinases such as trypsin, chymotrypsin and pronase, and glycosidases such as neuraminidase and galactosidase. Protein content in the erythrocyte membrane was $2.85{\pm}0.28$ in human, $3.60{\pm}0.41$ in Korean cattle, $3.71{\pm}0.36$ in Holstein, $4.13{\pm}0.83$ in Korean native goat and $3.94{\pm}0.56mg/ml$ in sheep, showing higher in ruminant animals than in human(p<0.01). Although the general protein profiles of the ruminant erythrocyte membranes were almost similar to that of human, all the ruminant erythrocyte membranes showed one additional protein band, called band-Q in the previous report on proteins of bovine erythrocyte membrane, which migrated electrophoretically to the mid position between band-2 and band-3 in human erythrocyte membranes. The glycoprotein profiles of ruminant erythrocyte membranes revealed by periodic acid Schiff(PAS) stain showed a marked difference from that of human. The PAS-1(glycophorin) and PAS-2(sialoglycogrotein) present in human erythrocyte membranes were almost absent from the ruminant animals. Instead, a strong PAS-positive band near the origin of the electrophorograms, which was named as PAS-B in the previous report on proteins of bovine erythrocyte membranes, was shown in the ruminant animals except sheep. In addition, the erythrocyte membranes of Korean native goat and sheep showed a moderate PAS-negative band near the tracking dye of the electrophorograms, which was named as PAS-G in this study. In the erythrocyte treated with the enzymes, the migration of each protein fracture of erythrocyte membranes in response to each enzyme was diverse according to different species or breed of ruminant animals. Among others, band-Q present in ruminants was slightly or moderately decreased by trypsin-, chymotrypsin-, and pronase- treatments of the erythrocytes, but not only in sheep. It was particularly noticeable that PAS-B, a fraction of glycoprotein, present in ruminants except sheep, was better digested by proteinases than by glycosidases, showing remarkable increase(p<0.01) of the ESR in accord with complete digestion(disappearance) of the PAS-B band by pronase, trypsin or chymotrypsin treatment of erythrocytes. In sheep, there was almost no any response to the various enzymes in general protein and glycoprotein profiles of the erythrocyte membranes except PAS-G, which was markedly decreased by pronase treatment of the erythrocytes. Nevertheless, the ESRs were accelerated in erythrocytes treated with pronase, trypsin, chymotrypsin and neuraminidase. Erythrocyte osmotic fragility was increased in erythrocytes treated with only pronase among five enzymes in all the human and ruminant animals used in this study.

• 한국철도학회논문집
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• 제13권2호
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• pp.186-193
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• 2010

철도교에서는 일정한 간격의 축중을 가지는 차량하중이 반복적으로 재하되므로 정적성능과 더불어 동적성능이 매우 중요하다. 또한 철도교의 상부에 부설되는 궤도시스템은 교량의 정 동적 성능에 영향을 주는 것으로 알려져 있다. 본 연구에서는 실제 궤도시스템을 적용한 거더시험체를 제작하여 궤도시스템에 따른 교량의 정 동적거동을 분석하였다. 정적거동 분석에서는 교량 처짐 및 응력을 검토하고 중립축위치를 분석하였으며, 동적거동 분석에서는 고유진동수, 감쇠비, 하중크기, 하중진폭에 대한 영향을 궤도시스템별로 검토하였다. 궤도부설에 따른 정적처짐 변화검토를 통해 궤도 부설전에 비해 자갈궤도는 약 7%, 콘크리트궤도는 약 50%의 강성 증가 효과가 있음을 확인하였고, 궤도 부설 시 교량의 고유진동수가 낮아졌으나 감쇠비 변화는 없는 것으로 분석되었다. 또한, 최대하중 크기가 증가할수록 철도교량의 동적응답(처짐 및 가속도)이 선형적으로 증가하였으며, 하중진 폭은 공진 시 교량의 동적응답을 크게 증가시키는 것으로 분석되었다. 따라서, 자갈궤도는 교량의 강성을 일정 부분 증가시키고, 콘크리트궤도의 경우 자갈궤도 부설 교량에 비해 상당한 강성기여도를 가지고 있음을 실험적으로 입증하였으나, 정량적인 강성기여도의 크기는 자갈궤도 및 콘크리트궤도의 설계값에 따라 상이할 수 있기 때문에 이를 적용할 수 있는 궤도의 질량 및 강성기여도 분석방법 개발이 필요할 것으로 판단된다.

• 한국통신학회논문지
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• 제27권6A호
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• pp.618-627
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• 2002

2차원 이산 웨이블릿 변환(2D-DWT)을 이용한 영상처리에서 영상의 경계부분 화소들을 처리하는 방법은 영상의 화질과 구현비용에 영향을 미친다. 본 논문에서는 하드웨어 및 소프트웨어 구현에 적합하고 화질의 손실이 거의 없는 효과적인 경계화소 처리방법을 제안하였다. 이 방법은 2차원 영상을 1차원 배열로 처리하는 방법으로, DWT 진행방향에 따라 영상을 직렬의 연속적인 데이터구조로 간주하고 DWT를 수행(Serial-Sequential Processing)한다. 제안한 방법의 성능 및 구현의 용이성을 보이기 위하여 영상을 압축하고 복원하는 영상압축 코덱을 구현하여 실험하였다. 여기에는 로그-스케일의 고정 양자화기를 사용하였으며, 엔트로피 코더는 구현하지 않았다. 실험결과 압축률 2:1 이상의 경우(엔트로피 코딩을 제외한 압축율) 주기적 확장(Periodic Expansion, PE)방법과는 거의 동일한 SNR(Signal to Noise Ration)을 보였으며, 대칭적 확장(Symmetric Expansion, SE)방법에 비해서는 15.3%, 0-화소 삽입(Zero-Padding Expansion, ZPE)방법에 비해서는 9.6% 높은 SNR을 보였다. 또한 주기적 확장방법은 본 논문의 방법에 비해 12.99%의 메모리가 더 필요하였으며, 영상의 압축동작만을 고려할 때 제안한 방법에 비해 SE 방법과

• 대한수의학회지
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• 제29권1호
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• pp.13-20
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• 1989

The proteins of the bovine erythrocyte membrane were analyzed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, and their relations to the slow sedimentation rate of bovine erythrocytes were investigated by treating the erythrocytes with trypsin. The erythrocyte sedimentation rates of bovine erythrocytes from Holstein and Korean native cattle were very slow compared with the human one (1/7 as slow as the human one) as reported previously. However, when human and Holstein erythrocytes were treated with trypsin (0.2 and 0.5 mg/ml) for 1 hour at ${37^{\circ}C}$, their sedimentation rates were markedly accelerated while the sedimentation rate of Korean native cattle's erythrocytes were not affected. Although the general protein profiles of the bovine erythrocyte membranes were almost similar to that of human, bovine erythrocyte membranes showed one additional protein band, called band Q in this study, which migrated electrophoretically to the mid-position between band 2 and band 3 in human erythrocyte membranes. Treatment of Holstein and human erythrocytes with trypsin caused a decrease or disapperance of the band Q from the erythrocyte membrane. Although the band Q in Korean native cattle's erythroyte membrane was decreased by trypsin treatment of the erythrocytes, the magnitude of the decrement was not so pronounced as in the case of human and Holstein erythrocytes. The glycoprotein profiles of the bovine erythrocyte membranes revealed by periodic acid-Schiff stain showed a marked difference from that of human. The PAS-1 (glycophorin) and PAS-2 (sialoglycoprotein) present in human erythrocyte membrane were almost absent from the bovine erythrocyte membranes. Instead, the bovine erythrocyte membranes showed a strong PAS-positive band near the origin of the electrophorograms, which is named as PAS-B in this study. The PAS-B band was disappered completely by the trypsin treatment of Holstein erythrocytes whereas the PAS-B band in Korean native cattle's erythrocyte membrane still remained after the trypsin treatment. The trypsin treatment of Korean native cattle's erythrocytes, however, led to the appearance of small molecular weight peptides, indicating that the high molecular weight glycoproteins were degraded by trypsin as in human and Holstein ones. These results suggest that the slow sedimentation rate of bovine erythrocytes is due in part to the presence of band Q protein fraction and PAS-B glycoprotein in the bovine erythrocytes.