• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.121-126
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• 2018

IEEE 802.1 TSN TG is developing standards for end-to-end delay bounds and zero packet loss based on Ethernet technology. We focus on packet forwarding techniques. TSN packet forwarding techniques can be classified into Synchronous and Asynchronous framework. Synchronous approach allocates fixed time period for a class, yet is complex for large networks. Asynchronous approach provides delay guarantee by regulator-scheduler pair, yet is unnecessarily complex, too. We propose network components for TSN Asynchronous architecture, which remove the complexity of maintaining flow state for regulation decisions. Despite such a simplicity, the proposed architecture satisfies the TSN's delay requirements provided the limited high priority traffic's maximum packet length.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.81-91
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• 2009

Recently, Chein et al proposed the ultralightweight strong authentication and strong integrity (SASI)protocol, where the tag requrires only simple bitwise operations. Since the tag does not support random number generator to generate a challenge nonce, an attacker can replay old messages and impersonate reader. However, all of the previous ultralightweight authentication schemes are vlunerable to various attacks: de-synk, eavesdropping, impersonating, tracking, DoS, disclosure etc. we analyze the problems of previous proposed ultrlightweight protocols, to overcome these security problems by using PRNG on the tag. Therefore, in this paper we propose a new lightweight RFID mutual authentication protocol that provides random number generator and bitwise operations, a security and an efficiency of the proposed schme analyze.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.55-55
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• 2020

개수로 흐름에서 유체특성을 파악하는 것은 매우 중요하다. 특히 홍수가 발생하거나 유속의 증가에 따라 유체의 거동은 복잡하고 예측하기 어려워진다. 이러한 복잡한 유체거동은 하천시설물 설계, 시공 및 관리에 있어서 구성재료의 보호능력에 따라 예상하지 못한 조건에서 쉽게 파손될 수 있다. 국내 하천의 경우 한계유속과 한계소류력에 의해 하천설계에 적용되고 있다. 한계 유속의 경우 간단한 수식에 의해 산정될 수 있지만 실제 하천의 보호능력을 대표하기는 힘들기 때문에 한계소류력이 동시에 고려되어야 한다. 한계소류력은 개수로 흐름에서 복잡하게 발생하는 이차류나, 난류 특성에 의해 산정하거나 예측하기는 매우 어렵다. 한계 소류력 뿐만 아니라 하천을 구성하는 재질의 조도계수 역시 균일하지 못하고 매우 예측하기 어렵다. 따라서 본 연구에서는 이러한 복잡한 양상을 나타내는 수리학적 요소에 대해 표준화된 실험수로에서 실험을 통해 평가하고, 체계화된 설계지침이 되고자 연구를 진행하였다. 본 연구에서는 자연하천과 유사한 조건의 경사를 가지는 경사수로와 경사의 영향에서 자유롭게 평가를 진행하고자 무경사수로에서 실험연구를 통해 제방 재료의 안정성 평가방법을 제시하고, 재체의 안정성 평가를 위한 실험진행은 기 개발된 바닥응력을 직접측정하는 장치와 PIV시스템을 이용하여 수리특성을 측정하였다.(Park J.H. et al. 2016, Flow Measurment and instrumentation.) 하천의 설계나 평가에 적용되는 평균 소류력 개념은 복잡한 난류흐름에서 평가지표로써 대표하기 힘들기 때문에 바닥에서 발생하는 소류력을 직접 측정하고, 측정된 소류력을 검증하고자 난류유속 u', v'을 이용하여 Reynolds stress산정하여 Total shear stress를 추정하는 기법을 사용하여 검증하고자 한다.

• Journal of the Korea Concrete Institute
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• v.26 no.1
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• pp.13-21
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• 2014

To quantitatively evaluate the influence of ground granulated blast-furnace slag (GGBS) as a supplementary cementitious material on the life-cycle environmental impact of concrete, a comprehensive database including 3395 laboratory mixes and 1263 plant mixes was analyzed. The life-cycle assesment studied for the environmental impact of concrete can be summarized as follows: 1) the system boundary considered was from cradle to pre-construction; 2) Korea life-cycle inventories were primarily used to assess the environmental loads in each phase of materials, transportation and production of concrete; and 3) the environmental loads were quantitatively converted into environmental impact indicators through categorization, characterization, normalization and weighting process. The life-cycle environmental impacts of concrete could be classified into three categories including global warming, photochemical oxidant creation and abiotic resource depletion. Furthermore, these environmental impacts of concrete was significantly governed by the unit content of ordinary portland cement (OPC) and decreased with the increase of the replacement level of GGBS. As a result, simple equations to assess the environmental impact indicators could be formulated as a function of the unit content of binder and replacement level of GGBS.

• Korean journal of applied entomology
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• v.43 no.2
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• pp.129-134
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• 2004

A simple and easy method was developed to monitor fungus gnats, Bradysia agrestis on sweet pepper in greenhouses. The larvae of B. agrestis were more attracted to potato discs than other sweetpotato, carrot, garlic, radish, and onion discs. The average numbers of B. agrestis found in each disc were 9.7 (potato), 6.0 (sweetpotato), 4.3 (carrot), 0.7 (garlic), 3.8 (radish), and 1.0 (onion). The number of larvae also increased by the size of disc surface and resulted in 2.1 larvae in 10${\times}$10${\times}$10 mm, 3.4 larvae in 20${\times}$20${\times}$10mm, and 3.9 larvae in 30${\times}$30${\times}$10 mm. The adults were more attracted to a yellow sticky trap (50.0 numbers) than a blue (18.0 numbers) or a white (3.7 numbers) traps. The optimal height for installing sticky trap in the greenhouse was determined as less than 50 cm from the rockwool bed based on the adults caught in the traps; 50.0 in less than 50 cm, 4.3 in 50-100 cm, and 2.0 in more than 100 cm height.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.330-337
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• 2018

In edentulous patients, implant - supported fixed prosthesis treatment has been proved to be useful, but involves complex treatment process. On the other hand, in the modern dentistry, digital technology has been developed day by day and it has expanded its range to the implant restoration of edentulous patients. In this case, a digital system was used for all stages of diagnosis, surgery, design and fabrication of provisional implants fixed prosthesis restoration in 66-year-old mandibular edentulous patients. In the preoperative diagnosis stage, a provisional restoration was designed based on the mucosal scan using the intraoral scanner and the stable occlusion of prefabricated complete denture of the patient. After flapless implant surgery using the surgical guide, the prefabricated interim restoration was connected to the implant and used as immediate provisional restoration. The final restoration was designed and fabricated by transferring the vertical dimension and the centric relation of the provisional restoration with stable occlusion using digital technology. We report a simple protocol of implant treatment in edentulous patients by using digital techniques to preserve the patient's vertical dimension and occlusion.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.3
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• pp.131-139
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• 2014

Infra-gravity waves (IGWs) with a period of 1~3 minutes are a factor that directly influences the motion analysis of moored ships inside a harbor and longshore sediment transport analysis. If significant levels of IGWs from far seas are transferred to a harbor and amplified, they may cause downtime of large ships and induce economic loss. In this study, transfer characteristics of the IGWs intruding from outside to inside Pohang New Harbor were analyzed using statistical analysis and transfer function of wave data measured at both outside and inside the harbor for around 5 years. Transfer characteristic analysis was limited to events where IGWs had wave heights above 0.1 m. The wave height distribution of inside the harbor was similar to that of outside the harbor, while the wave period variance of the former was larger than that of the latter. The parameters of the transfer function was optimally estimated according to each event. The estimated average RMS error of the wave height inside the harbor was around 0.013 m. The estimated parameters had a strong correlation with the linear combination information of IGW wave height, period, and direction (R = 0.95). The transfer function suggested in this study can quickly and easily estimate information on IGWs inside the harbor using IGW information predicted beforehand, and is expected to reduce damage due to unexpected restrictions on harbor usage.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.82-82
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• 2001

본 연구는 한우에 있어서 인공수정후 수태율증진을 위한 기초자료를 확보할 목적으로 성숙 미경산 한우의 발정동기화를 위해 CIDR(EAZI-BREED CIDR Plus, USA)를 7일간 질내에 삽입하였고, CIDR처리 제 6일째에 PGF2$\alpha$(lutlyase, USA)제제 5 $m\ell$을 근육주사하여 발정이 유기된 92%의 개체를 인공수정을 실시하였다. 수태율증진을 위해 무처리구를 두었고, hCG처리구(Chorulon, Intervet, Netherlands)는 2000IU를 근육 주사하였으며, CIDR처리구에는 Estradiol-17$\beta$의 캡슐을 제거한 CIDR를 수정후 7일부터 일주일간 질내에 삽입 처리하여 각 처리당 15두씩 총 45두의 한우를 실험에 공시하였다. 발정이 유기된 개체는 인공수정후 30일까지 2일 간격으로 채혈하여 혈중 Progesterone, IGF, IGF-II 및 cortisol 농도를 RIA법으로 분석하였으며 수정 후 60일 이후에는 직장검사법으로 임신감정을 실시하였다. 수정후 수태율은 대조구와 CIDR 처리구에서는 평균 62%였으나 hOG처리구는 73%로서 대조구에 비해 유의적으로 수태율이 높게 나타났다. 이때의 혈중 progesterone농도를 분석한 결과, 대조구에 CIDR 처리구의 수정후 7일째부터 증가하기 시작하여 제 12일째에서 평균 5.5ng/$m\ell$까지 증가하다가 그 이후 재발정 예정일일 21일째에 다소 감소되다가 다시 증가되어 일정한 수준으로 유지되었다 그러나 hCG처리구의 경우 수정후 5일부터 progesterone이 증가하다가 제 15일까지 약 10ng/$m\ell$까지 높은 progesterone이 유지되었다. 이와 같은 결과로 보아 hCG는 혈중 progesterone농도를 증가시킴으로써 난소내 임신황체의 progestorone분비 능을 촉진시키는 작용을 하는 것으로 사료되나, 한편 혈중 IGF I과 IGF-II농도는 대조구, hCG처리구 및 CIDR 처리구간의 차이가 없이 수정 후 제10일까지는 다소 높은 수준이었으나 그 이후 감소되는 현상으로 혈중 progesterone농도와는 부의 상관관계를 보였다. 따라서 IGF-I과 IGF-II는 혈중 progesterone의 농도를 인위적으로 조절하거나 황체의 progesterone분비기능을 직접 조절하는 역할은 하지 않는 것으로 사료되며, 특히 초기 임신의 수태율에 직접적으로 영향이 없는 것으로 사료된다. 또한 혈중 cortisol농도는 처리간의 차이는 확인할 수 없으나 임신과 비임신간의 혈중 cortisol농도는 유의적으로 차이가 있는 것으로 나타났다. 본 실험의 결과로 인공수정이나 수정란이식 및 체세포복제 수정란뿐만 아니라 형질전환 수정란의 이식후 수태율을 증진시켜 첨단기술의 조기정착을 위해 이식 후 7일째나 인공수정 후 7일째 hCG제제를 근육주사로 간단하게 처리함으로써 수태율을 크게 개선될 수 있으며 이것은 난소의 황체기능 즉, 황체로부터 충분한 progesterone을 분비할 수 있는 내분비적 환경을 제공하는 것으로 사료된다.

• Journal of Advanced Navigation Technology
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• v.12 no.2
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• pp.100-108
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• 2008

In this paper, the dual-ground, high-gain and broad-band internal antenna has been designed and fabricated for 4th-generation mobile communication applications. The optimized antenna was fabricated using photolithography method. The antenna consist of the patches, antenna and system ground, and a probe. The patch and ground plane were separated by air. In order to prevent the demage due to radiator swaying, the foams(${\varepsilon}_r{\fallingdotseq}1.03$) were used to fix the patches and ground. The conductor for the radiators was 0.05 [mm] thick. The measured input return loss showed less than -10 [dB] at the broadband from 3499 to 4743 [MHz]. It's measured bandwidth was 1244 [MHz]. The radiation patterns measured at 3400, 3600, 3800, 4000 and 4200 [MHz] showed Omni-directional characteristics. The gain in the E-plane and H-plane was 4.7 ~ 6.1 and 2.1 ~ 4.3 [dBi], respectively.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.337-343
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• 2014

This paper presents a continuum-based shape design sensitivity analysis(DSA) method for crack propagation problems using a reproducing kernel method(RKM), which facilitates the remeshing problem required for finite element analysis(FEA) and provides the higher order shape functions by increasing the continuity of the kernel functions. A linear elasticity is considered to obtain the required stress field around the crack tip for the evaluation of J-integral. The sensitivity of displacement field and stress intensity factor(SIF) with respect to shape design variables are derived using a material derivative approach. For efficient computation of design sensitivity, an adjoint variable method is employed tather than the direct differentiation method. Through numerical examples, The mesh-free and the DSA methods show excellent agreement with finite difference results. The DSA results are further extended to a shape optimization of crack propagation problems to control the propagation path.