• Earthquakes and Structures
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• 제11권3호
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• pp.387-406
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• 2016

The main purpose of this paper is to determine the dynamic characteristics and the structural stability of the two approach viaducts of the Bosphorus Suspension Bridge under the expected stresses that would be caused during earthquake conditions. The Ortakoy and the Beylerbeyi approach viaducts constitute the side spans of the bridge at two locations. The bridge's main span over the Bosphorus is suspended, whereas they are supported at the base at either end. For the numerical investigation of the viaducts, 3-D computational structural finite element-FE models were developed. Their natural frequencies and the corresponding mode shapes were obtained, analyzed, presented and compared. The performances of the viaducts, under earthquake conditions, were studied considering the P-Delta effects implementing the push-over (POA) and the non-linear time-history analyses (NTHA). For the NTHA, three earthquake ground motions were generated depending on the location of the bridge. Seismic performances of the viaducts were determined in accordance with the requirements of the Turkish Seismic Code for the Earthquake Design of Railways Bridges (TSC-R/2008) and those of Caltrans (CALTRANS-2001) given for Seismic Design of Steel Bridges, separately. Furthermore, the investigation was extended for evaluating the possible need for retrofitting in the future. After the analysis of the resultant data, a retrofit recommendation for the viaducts was presented.

• 정보처리학회논문지D
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• 제10D권2호
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• pp.309-316
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• 2003

본 논문에서는 대역확산 방식을 응용한 새로운 워터마킹 기법과 이를 이용한 semi-fingerprinting 시스템 구조를 제시하며, 특히, 저작권 보호에 주초점이 맞추어져 있는 워터마크 기술을 fingerprinting 분야에 적용함으로써 그 동안 학문연구에 그치고 있었던 워터마크 기술을 보다 현실적인 응용에까지 확대시키기 위한 방법을 제시한다. 본 논문에서 제안하는 워터마킹 기법은 대역확산 방식중 random number shift 방법을 이용하여 데이터 삽입량을 증가시키는 방법의 일종이며, 삽입되는 데이터량이 60-bits이고, 20-bits CRC코드를 이용하여 추출된 정보의 신뢰도를 높였다. 또한, semi-fingerprinting에 적용하기 위해서 cIDf(content ID forum)의 지침을 기반으로 워터마크를 구성하였다.

• Geomechanics and Engineering
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• 제15권3호
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• pp.879-888
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• 2018

Probability-based design codes have been developed to sufficiently confirm the safety level of structures. One of the most acceptable probability-based approaches is Load Resistance Factor Design (LRFD), which measures the safety level of the structures in terms of the reliability index. The main contribution of this paper is to calibrate the load and resistance factors of the design code for tunnels. The load and resistance factors are calculated using the available statistical models and probability-based procedures. The major steps include selection of representative structures, consideration of the limit state functions, calculation of reliability for the selected structures, selection of the target reliability index and calculation of load factors and resistance factors. The load and resistance models are reviewed. Statistical models of resistance (load carrying capacity) are summarized for strength limit state in bending, shear and compression. The reliability indices are calculated for several segments of a selected circular tunnel designed according to the tunnel manual report (Tunnel Manual). The novelty of this paper is the selection of the target reliability. In doing so, the uniform spectrum of reliability indices is proposed based on the probability paper. The final recommendation is proposed based on the closeness to the target reliability index.

• Journal of Welding and Joining
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• 제16권2호
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• pp.100-110
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• 1998

In this paper, the laser weldability of thin gage steels for automobile application is discussed. Welding was carried out with a high power carbon dioxide laser system, and the laser energy was concentrated through a plano-convex lens. Test results showed that the joint gap in the butt welding proved to be one of the critical conditions for an acceptable weld. In the case where the ratio of the gap clearance to the material thickness was slightly bigger than optimal value, the weld strength was reduced showing weld metal fracture. It was possible to obtained a weld penetration ratio of 0.91 when the vertical offset ratio was controlled to be 0.4 or smaller. Results also demonstrated that the weld strength of the lap joint was influenced by travel speed. At the travel speeds lower than 37 mm/s, the weld strength indicated higher value than that of class A recommendation strength of a resistance spot weld based on the KS code. It was clear that the complicated effect of specimen alignment should be considered so as to make a sound weld with high integrity when the laser process was applied to the long weld line.

• 한국안전학회지
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• 제25권6호
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• pp.146-154
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• 2010

In this study the experimental results of fatigue specimen for the Strand Stay Cable Assembly of Extadosed bridges is investigated. The fatigue test and tensile experiment is conducted to 6 kinds of specimens. Test specimen OVM250-31 Strand Cable System manufactured by china OVM B-Machinery Co., Ltd, and OVM250-42 Parallel Strand Stay Cable Assembly manufactured by china OVM B-Machinery Co., Ltd, are passed for fatigue test and rupture tensile test. But Test specimen OVM250-42 Parallel Strand Stay Cable Assembly manufactured by korean A-Machinery Co., Ltd, is not passed for fatigue test conducted according to the "Recommendation for Stay Cable Design. The test result are compared to the fatigue criteria of PHI 2001 for cyclic load, and it is concluded that the current korean design code will be needed for representing the fatigue load in Hot Dip Galvanized Strand Stay Cable. It is verified that the new korean specification and quality criteria of Strand Stay Cable and exact experimental applied process will be needed.

• Nuclear Engineering and Technology
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• 제50권5호
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• pp.639-647
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• 2018

In this study, the effects of selecting water/silver nanofluid as both a coolant and a reactivity controller during the first operating cycle of a light water nuclear reactor are investigated. To achieve this, coupled neutronic-thermo-hydraulic analysis is employed to simulate the reactor core. A detailed VVER1000/446 reactor core is modeled in monte carlo code (MCNP), and the model is verified using the porous media approach. Results show that the maximum required level of silver nanoparticles is 1.3 Vol.% at the beginning of the cycle; this value drops to zero at the end of cycle. Due to substitution of water/boric acid with water/Ag nanofluid, reactor operation time at maximum power extends to 357.3 days, and the energy generation increases by about 27.3%. The higher negative coolant temperature coefficient of reactivity in the presence of nanofluid in comparison with the water/boric acid indicates that the reactor is inherently safer. Considering the safety margins in the presence of the nanofluid, minimum departure from nucleate boiling ratio is calculated to be 2.16 (recommendation is 1.75).

• 한국산업보건학회지
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• 제11권2호
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• pp.126-134
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• 2001

Statistical approaches for analysis of data from the limited number of samples in ship building industry(SBI) collected by an industrial hygienist for checking compliance to an occupational standard were considered. Sampling for compliance usually has been guided by judgment selection, rather than true randomness, resulting in the creation of compliance samples which approximate a censored sample from the upper tail of the exposure distribution. Similar exposure groups(SEGs) including welding and painting process were established to assess representative values in each groups after reviewing the whole production line in SBI. For the convenient statistical approaches, the code has assigned to each SEGs. The descriptive statistics and probability plotting were used to yield the representative values in each SEGs. In the first step, SEGs of 558 were established from 5 ship building companies. The 38 SEGs showed the uncertainty are divided into each 5 companies and assessed the representative values again. The 44 SEGs in each companies was not showed the normal and lognormal distribution was analyzed each data. And also, recommendation was suggested to resolve the uncertainty in each groups.

• 한국문헌정보학회지
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• 제21권
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• pp.61-101
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• 1991

This study reviews the development and change of main entry principle in German cataloging codes, with special emphasis on RAK. With rerard to the functions of catalog, comparison between the traditional title main entry in the Orient and author main entry in the West has been made. The analysis confirms in this study that various criteria in choice of the entries in RAK have been adopted. In case of works where the persons who have played different roles in the works are named on the title page, as well as related works and works of mixed responsibility, the criteria of entry determination are complex and time consuming process and have no absolute value. And there are also various kinds of problems in corporate entries including confirmation of originator(Urheber), choice of either the territorial authority corncerned or corporate bodies as an entry depending on the nature of the publications, and a unique bibliographical situation of treaties. This means the code is absence of absolute value in selecting entries, and this results in adoption of main entry principle which has lost its significance for the purpose of cataloging. With emergence of the ISBD and actualization of automated cataloging, morever, all entries are equal as points of access. It would eliminate the need for personal judgements required in choice of main entry by the present code. In doing so, it would bring uniformity and standardization to cataloging practice. In direct approach to works, title entry is more developed finding device than author entry in cataloging theories. Thus introduction of unit card system beginning with title which is adopted in KCR3 would be desirable, the complicated rules for the choice of entry could be abandoned from cataloging codes. Most of the user studies show that catalog users have placed higher value on the title entry as a finding device and each entry is equal as access points through unit entry. This means that choice of a given entry as a main entry is unnecessary in cataloging codes. Title entry would be a rather simple standard and direct approach for works. This study proves that the traditional title entry of Korea is superior to author main entry in the Western world in cataloging theory. Thus recommendation to be made is that abandonment of author main entry from cataloging codes should be considered in the future.

• 한국어병학회지
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• 제23권1호
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• pp.99-106
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• 2010

수산동물의 질병 발생과 확산을 억제하기 위하여 제정된 수산동물질병관리법은 2008년 12월 22일 시행되었다. 수산동물의 질병 발생과 확산을 억제하기 위하여 위험분석이 새롭게 도입 되었다. 수산동물의 이동에 대한 위험분석의 도입은 세계무역기구의 SPS 협정의 권고사항의 이행과 관련이 있으며, 세계동물보건기구의 수산동물위생규정의 지침에 의거하여 수행되어져야 한다. 이 보고서는 수산동물의 이동에 대한 국제규정과 국내의 위험분석 제반여건을 수집하여 분석하였다.

• 한국전자거래학회지
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• 제13권4호
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• pp.173-191
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• 2008

오늘날 인터넷의 전반적인 보급 및 전자상거래의 확산으로 인하여 정보의 홍수를 이루게 되었고, 고객들은 자신이 원하는 제품이나 서비스를 선택하기 위해서 정보를 탐색하는 작업이 더욱 어려워지게 되었다. 이러한 고객들에게 좀 더 편리하게 자신이 원하는 제품이나 서비스를 선택하도록 도와주는 것이 추천 시스템으로서, 고객 관계 관리의 중요한 부분으로 자리 잡게 되었다. 본 연구에서는, 인터넷 서점을 이용하는 고객에게 그가 관심을 가질만한 서적을 추천하여 줌으로써 구입할 서적의 선택을 도와주는 서적 추천 시스템을 개발하였다. 기존의 서적 추천 시스템 개발에 협업 필터링 기법이 주로 활용되어 왔다. 하지만 협업 필터링 기법을 적용하기 위해서는 각 서적에 대한 구매자들의 평가치가 수집되어야 하는데, 이러한 평가치들은 시스템 개발 이전에 오랜 기간에 걸쳐 정교한 계획 하에서 수집되어야 한다. 더욱이 구매자들이 평가치 제공에 협조하지 않을 경우에는 추천 시스템 자체의 작동이 불가능하게 된다. 그러므로 본 연구에서는 고객들의 구매기록만으로 서적 추천을 수행할 수 있도록 사례기반추론 기법을 활용하여 시스템을 개발 하였는데, 서적의 소분류 코드를 예측하는 상황에서 약 40% 수준의 적중률을 보였다.