The PoN (Proof of Nonce) distributed consensus algorithm basically uses a non-competitive consensus method that can guarantee an equal opportunity for all nodes to participate in the block generation process, and this method was expected to resolve the first trilemma of the blockchain, called the decentralization problem. However, the decentralization performance of the PoN distributed consensus algorithm can be greatly affected by the network transaction transmission delay characteristics of the nodes composing the block chain system. In particular, in the consensus process, differences in network node performance may significantly affect the composition of the congress and committee on a first-come, first-served basis. Therefore, in this paper, we presented a problem by analyzing the decentralization performance of the PoN distributed consensus algorithm, and suggested a fairness control algorithm using a learning-based probabilistic acceptance rule to improve it. In addition, we verified the superiority of the proposed algorithm by conducting a numerical experiment, while considering the block chain systems composed of various heterogeneous characteristic systems with different network transmission delay.

In anion exchange membrane fuel cells, Pd nanoparticles are extensively studied as promising non-Pt catalysts due to their electronic structure similar to Pt. In this study, to fabricate Pd nanoparticles well dispersed on carbon support materials, we propose a synthetic strategy using mixed organic ligands with different chemical structures and functions. Simultaneously to control the Pd particle size and dispersion, a ligand mixture composed of oleylamine(OA) and trioctylphosphine(TOP) is utilized during thermal decomposition of Pd precursors. In the ligand mixture, OA serves mainly as a reducing agent rather than a stabilizer since TOP, which has a bulky structure, more strongly interacts with the Pd metal surface as a stabilizer compared to OA. The specific roles of OA and TOP in the Pd nanoparticle synthesis are studied according to the mixture composition, and the oxygen reduction reaction(ORR) activity and durability of highly-dispersed Pd nanocatalysts with different particles sizes are investigated. The results of this study confirm that the Pd nanocatalyst with large particles has high durability compared to the nanocatalyst with small Pd nanoparticles during the accelerated degradation tests although they initially indicated similar ORR performance.

Corrosion inhibitors including calcium hydroxide have been used to prevent corrosion in the pipes for tap water supply. The corrosion index (i.e., Langelier Index) differs by area and water quality. The corrosion indices of the areas studied differed by more than 2.0. The ‘homogenized’ calcium hydroxide was added to the treated water at the K water treatment plant, in order to increase the value of the corrosion index and the concentration of calcium. As the result, the concentration of calcium was increased while the turbidity and pH changed little. The corrosion rate of the tap water with the 'homogenized' calcium hydroxide could be slowed down pretty much. The results suggested that the technology of 'homogenization' of calcium hydroxide can applied to tap water and desalinated water to prevent corrosion in water pipes even in corrosive pipes.

Gd2O3:Eu3+ red phosphors were prepared by template method from crystalline cellulose impregnated by metal salt. The crystallite size and photoluminescence(PL) property of Gd2O3:Eu3+ red phosphors were controlled by varying the calcination temperature and Eu3+ mol ratio. The nano dispersion of Gd2O3:Eu3+ was also conducted with a bead mill wet process. Dependent on the time of bead milling, Gd2O3:Eu3+ nanosol of around 100 nm (median particle size : D50) was produced. As the bead milling process proceeded, the luminescent efficiency decreased due to the low crystallinity of the Gd2O3:Eu3+ nanoparticles. In spite of the low PL property of Gd2O3:Eu3+ nanosol, it was observed that the photoluminescent property was recovered after re-calcination. In addition, in the dispersed nanosol treated at 85 oC, a self assembly phenomenon between particles appeared, and the particles changed from spherical to rod-shaped. These results indicate that particle growth occurs due to mutual assembly of Gd(OH)3 particles, which is the hydration of Gd2O3 particles, in aqueous solvent at 85 oC.

Poly-methylmetacrylate (PMMA) is mainly applied in the plastic manufacturing industry, but PMMA is weak and gradually got discolor. The strength of PMMA can be improved through organic-inorganic hybrid nano composites with inorganic nano particles such as, SiO2 or ZrO. However, inorganic nano particles are mostly agglomerated spontaneously. In this study, the zeta potential is controlled using different types of organic solvent with different concentrations, dispersibillity of SiO2 nano particles on the PMMA particle are analyzed. When 3 M acetic acid is used, absolute value of the zeta potential is higher, SiO2 nano particle is well attached, and dispersed on the PMMA particle surface. Results indicate that the absolute value of the zeta potential affects the stability of SiO2 dispersion.

Pt nanopowder-dispersed SiO2 (SOP) films were prepared by RF co-sputtering method using Pt and SiO2 targets in Ar atmosphere. The growth rate and Pt content in the film were controlled by means of manipulating the RF power of Pt target while that of SiO2 was fixed. The roughness of the film was increased with increasing the power of Pt target, which was mainly due to the increment of the size and planar density of Pt nanopowder. It was revealed that SOP film formed at 10, 15, 20 W of Pt power contained 2.3, 2.7, and 3.0 nm of spherical Pt nanopowder, respectively. Electrical conductivity of SOP films was exponentially increased with increasing Pt power as one can expect. Interestingly, conductivity of SOP films from Hall effect measurement was greater than that from DC I-V measurement, which was explained by the significant increase of electron density.

건축 및 토목 구조물의 진동 제어분야에서 중앙집중식 제어방식은 주어진 목표응답수준을 만족시키기 위해서 전력공급, 센서, 그리고 감쇠기 등을 포함하는 복잡한 제어시스템을 구축하고 유지하는 노력이 필요하고, 구조물 유한요소모델의 큰차수, 모델의 불확실성, 가력장치의 제한 등의 이유로 적용성의 한계가 있다. 본 논문에서는 센서 혹은 컴퓨터없이 준능동 MR 감쇠기가 설치된 층만의 정보에 의해 제어력이 생성되는 분산제어식 응답의존형 MR 감쇠기가 제안하였다. 제안된 분산제어식 응답의존형 MR 감쇠기는 구조물의 층전단력에 대한 가변마찰력 크기 비의 변화에 따라 지진하중을 받는 구조물의 제어성능이 수동인 경우와 비선형 시간이력해석을 통해 비교 평가되었다. 마지막으로 일반 제어이론에서 널리 이용되는 중앙집중식 LQR 알고리듬과 본 논문에서 제안된 분산제어식 응답의존형 MR감쇠기가 3층 전단형 구조물을 대상으로 수치해석을 통해 비교 평가됨으로써 제안된 알고리즘의 유효성을 검증하였다.

4 세대 무선망에서 이 기종 엑세스 망간의 핵심기술은 망 선택기법과 호 수락제어이다. 본 연구에서는 차세대 무선망의 이 기종 엑세스 무선망으로 CDMA-OFDMA 망을 고려하여, 이 망에 적합한 퍼지 신경망 분산 상향링크 호 수락제어를 제안한다. 제안된 기법은 이종 무선망에서 원하는 신규호의 차단확률과 서비스 진행 중인 호의 강제종료확률을 만족시키면 서, 무선자원의 효율적인 사용을 목적으로 한다. 호 수락의 결정은 무선 엑세스 망의 상향 링크에서 퍼지 추론과 신경망 학습에 의한 추정된 전력값 과 미리 결정한 상향 전력 한계값 을 비교하여 모바일 터미널에서 결정한다. 시뮬레이션을 통하여 제안한 기법의 성능을 신경 망 입력노드의 수에 따른 평균 거절율과 섹터 당 평균 이동국 수에 따른 호 손실율 및 거 절율을 평가 하였다. 그 결과 제안된 기법을 사용하는 무선망은 원하는 서비스 품질을 만족 하면서 부하의 증가에 따른 효율적인 호 수락제어가 이루어짐을 보인다.

Recently, buildings are constructed increasingly higher and even more people are using elevators every day. Therefore, more efficient means of vertical transportation are required. Most of high-rise buildings is equipped with elevators. Unlike one elevator system, a multi-elevator system requires a function, which can distribute multiple elevators effectively. This paper examines a multi-elevator system, which has been modeling mathematically, in order to reduce waiting time and use elevators more effectively.

본 논문에서는 응력파 전파를 수치모의할 때 발생하는 수치적인 분산효과를 제거하기 위해 파동방정식에 기초한 일차원 유한요소모형을 이용하여 수치분산오차의 특성을 분석하고 분산오차를 제어할 수 있는 방법을 제안하였다. 질량행렬을 그대로 사용하는 경우와 집중질량행렬을 사용하는 경우에 대한 수치분산오차를 분석하였다. 개발된 분산제어기법은 공간미분항의 시간단계 가중치 및 질량집중도를 조정하는 음해법과 인위적인 분산항을 추가하는 양해법의 두가지 방법이다. 제안된 분산보정기법을 이용하여 계산한 수치해와 파동방정식의 해석해를 비교한 결과 본 연구에서 제안한 분산보정기법의 타당성을 확인하였다.

서비스 지향 구조(SOA, Service Oriented Architecture)는 인터넷상에서 구현되는 웹 서비스의 출현으로 인하여 급속도로 발전하고 있으며 활성화 되고 있다. 인터넷 환경이 발달함에 따라 분산되어 있는 자원에 쉽게 접근할 수 있고, 시맨틱 웹이란 기술로 보다 광범위하게 지식과 자원을 표현할 수 있다. 그러나 웹 서비스의 사용과 이에 따른 지식과 자원을 보호하기 위해서는 정보보안이 필수 요건이나 웹 서비스의 활성화에 비하여 웹 서비스의 보안 표준이나 웹 서비스 보안이 미비한 상태이다. 본 논문에서는 이러한 요건을 충족하기 위하여 CPC(Collaborative Product Commerce) 웹 서비스를 위한 접근제어 프로세서를 제안한다. 각각의 CPC 웹 서비스마다 독립적인 접근제어 프로세서를 설계하기 위하여 기본적으로 사용할 수 있는 웹 서비스 표준과 개념에 따라 통합 웹 서비스를 위한 분산 접근제어 프로세서를 설계한다.