• Title/Summary/Keyword: Cluster theory

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Effect of Basis Set Superposition Error on the MP2 Relative Energies of Gold Cluster Au6

  • Kim, Kyoung-Hoon;Kim, Jong-Chan;Han, Young-Kyu
    • Bulletin of the Korean Chemical Society
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    • v.30 no.4
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    • pp.794-796
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    • 2009
  • We have studied the structures and stabilities of Au6 to explore the origin of the large discrepancy between relative energies obtained from the density functional theory (DFT) and ab initio correlated levels of theory. The MP2 methods significantly overestimate the stability of the non-planar isomer when the double-$\zeta$ polarization quality of basis sets, such as LANL2DZ+1f and CEP31G+1f, are used. However, we show that such preference for the non-planar structure at the MP2 level mainly originates from the large basis set superposition error.

Time-resolved polarization and depolarization tracking on reaction pathway of calcium carbonates in a view of non-classical nucleation theory (비전통핵생성 이론 관점에서 탄산칼슘의 반응경로에 대한 시간분해 분극 및 탈분극 추적)

  • Kim, Gwangmok
    • Journal of Urban Science
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    • v.9 no.2
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    • pp.45-50
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    • 2020
  • The formation characteristics of calcium carbonates are closely related to the durability and mechanical properties of cement-based materials. In this regard, a deep understanding of the reaction pathway of calcium carbonates is critical. Recently, non-classical nucleation theory was summarized and it was presumed that prenucleation clusters are present. The formation of the prenucleation cluster at undersaturated condition (≈ 0.1 ml) in the present study was investigated via electrical characteristics of an electrolytic solution. Calcium chloride dihydrate (CaCl2·2H2O) and sodium carbonate (Na2CO3) were used as starting materials to supply calcium and carbonate sources, respectively. Furthermore, the reaction pathway of calcium carbonates was investigated by time-resolved polarization and depolarization characteristics of the electrolytic solution. The time-resolved polarization and depolarization tests were conducted by switching polarity with an interval of 20 seconds for 1 hr and by measuring the variation of electrical resistance. It can be inferred from the results obtained in the present study that the reactive constituent for the formation of calcium carbonates was mostly consumed in the period possibly associated with the prenucleation and the reaction pathways may be governed by the monomer-addition mechanism.

GT-PSO- An Approach For Energy Efficient Routing in WSN

  • Priyanka, R;Reddy, K. Satyanarayan
    • International Journal of Computer Science & Network Security
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    • v.22 no.4
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    • pp.17-26
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    • 2022
  • Sensor Nodes play a major role to monitor and sense the variations in physical space in various real-time application scenarios. These nodes are powered by limited battery resources and replacing those resource is highly tedious task along with this it increases implementation cost. Thus, maintaining a good network lifespan is amongst the utmost important challenge in this field of WSN. Currently, energy efficient routing techniques are considered as promising solution to prolong the network lifespan where multi-hop communications are performed by identifying the most energy efficient path. However, the existing scheme suffer from performance related issues. To solve the issues of existing techniques, a novel hybrid technique by merging particle swarm optimization and game theory model is presented. The PSO helps to obtain the efficient number of cluster and Cluster Head selection whereas game theory aids in finding the best optimized path from source to destination by utilizing a path selection probability approach. This probability is obtained by using conditional probability to compute payoff for agents. When compared to current strategies, the experimental study demonstrates that the proposed GTPSO strategy outperforms them.

Assessing Density Functional Theories to Compute the OH Stretching Frequencies of Water Molecules in Condensed Phases (응축상 물 분자의 OH 수축 진동수 계산을 위한 전자밀도 범함수 비교)

  • Kiyoung, Jeon;Mino, Yang
    • Journal of the Korean Chemical Society
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    • v.67 no.1
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    • pp.13-18
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    • 2023
  • We evaluate electron density functional theories for the computation of 0-1 and 1-2 transition energies of local OH stretching motion of water molecules in condensed phases. By examining thirteen density functionals and nine sets of basis functions, it was found that the optimal combination that predicts the transition energies highly correlated with those calculated by the coupled cluster theory, CCSD(T), is the hybrid density functional theory developed by Head-Gordon group, ωB97X(D)/6-31+G*.

An Integrative Research on Chinese Automobile Industry in Three Economic Blocs: Focusing on Technological Learning, Architecture, and Cluster Approach (중국 3대 경제권 자동차 산업에 대한 연구: 기술학습, 아키텍처, 클러스터를 중심으로)

  • Baek, Seo-In;Kim, Hee-Tae;Kwon, Sang-Jib
    • Knowledge Management Research
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    • v.15 no.4
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    • pp.147-170
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    • 2014
  • This study investigates the main characteristics of Chinese automobile industry based on the technology learning, architecture theory and cluster. As a case study sample, we chose three most representative automobile firms from three main cities in China, FAW from northern part of China, SAIC from middle part of China, and BYD from southern part of China. According to the research findings, FAW has equipped self-production ability in virtue of political support but felled behind in future transportation due to lack of convergence with local cluster. In case of SAIS, similar phenomenon happened in spite of highest purchasing power of shanghai. BYD has achieved great quantum jump through the aggressive investment strategy in electric vehicle even though there are still many technological learning and experience to be cumulated. Overall, this research extends the current literature on key roles (technological learning, architecture, and cluster features) in the automobile industry growth by suggesting their crucial aspects in knowledge management and strategic planning to a newly emerging market, China, and sheds light on the relationship between regional characteristics and automobile growth.

Fail Over Analysis and Management for the Database Implement of the High Availability Solution (고가용성 데이터베이스 구축을 통한 장애 극복 분류 및 관리 기법)

  • Lee, Byoung-Yup
    • The Journal of the Korea Contents Association
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    • v.10 no.7
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    • pp.49-54
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    • 2010
  • In these days, Internet environment are very quickly development as well On-line service have been using a online for the mission critical business around the world. As the amount of information to be processed by computers has recently been increased there has been cluster computing systems developed by connecting workstations server using high speed networks for high availability. As a result, this study on a cluster based DBMS and common solution of DBMS venders has been studying with a wide range, as well as It is not good study a management skill for the cluster-based DBMS efficiently and optimization. accordingly, This study find out optimization managements skill and theory of he High availability solution on cluster-based DBMS.

Vibrational Analysis and Intermolecular Hydrogen Bonding of Azodicarbonamide in the Pentamer Cluster

  • Lee, Choong-Keun;Park, Sun-Kyung;Min, Kyung-Chul;Kim, Yun-Soo;Lee, Nam-Soo
    • Bulletin of the Korean Chemical Society
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    • v.29 no.10
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    • pp.1951-1959
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    • 2008
  • Pentamer cluster of azodicarbonamide (ADA) based on the crystalline structure was investigated for the equilibrium structure, the stabilization energies, and the vibrational properties at various levels of the density functional theory. Stretching force constants of N${\cdot}{\cdot}{\cdot}$H or O${\cdot}{\cdot}{\cdot}$H, and angle-bending force constants of N-H${\cdot}{\cdot}{\cdot}$N or N-H${\cdot}{\cdot}{\cdot}$O for intermolecular hydrogen bonds in the pentamer cluster were obtained in 0.2-0.5 mdyn/$\AA$ and 1.6-2.0 mdyn$\AA$, respectively. The geometry of central ADA molecule fully hydrogen bonded with other four molecules shows good coincidence to the crystalline structure except the bond distances of N-H. Calculated Raman and infrared spectra of central ADA molecule in cluster represent well the experimental spectra of ADA obtained in the solid state compared to a single molecule. Detailed structural and vibrational properties of central ADA molecule in the pentamer cluster are presented.

The Role of Economic Cluster Perspectives in Regional Economic Development

  • Haak, Robert;Vora, Gautam;Walsh, Steven T.;White, Craig G.
    • World Technopolis Review
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    • v.3 no.1
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    • pp.17-29
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    • 2014
  • The importance of science and technology as the root of exceptional regional economic development has been extolled since the time of Schumpeter. Today emerging technologies are signaling the start of a new economic cycle where regions that are effective in technology translation will gain advantage. The will of policymakers to translate technology into regional job and wealth creation seems to be at an all-time high. Yet an improved process for translating technical development into regional prosperity has proved elusive. If there are no processes other than applying techniques that have worked in the past for other regions to a new region then there is cause for concern. Here the authors seek to add to this field of knowledge by applying elements of the varied cluster theories to provide a basis for policy for regional economic development by turning science and technology into commercial innovation. We provide a review of current cluster theories and discuss the positive and negative issues associated with each. We propose a model that allows interested professionals to utilize aspects of each cluster perspective geared to the realities of their specific area.

Some Calculated (p,α) Cross-Sections Using the Alpha Particle Knock-On and Triton Pick-Up Reaction Mechanisms: An Optimisation of the Single-Step Feshbache-Kermane-Koonin (FKK) Theory

  • Olise, Felix S.;Ajala, Afis;Olaniyi, Hezekiah B.
    • Nuclear Engineering and Technology
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    • v.48 no.2
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    • pp.482-494
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    • 2016
  • The Feshbache-Kermane-Koonin (FKK) multi-step direct (MSD) theory of pre-equilibrium reactions has been used to compute the single-step cross-sections for some (p,${\alpha}$) reactions using the knock-on and pick-up reaction mechanisms at two incident proton energies. For the knock-on mechanism, the reaction was assumed to have taken place by the direct ejection of a preformed alpha cluster in a shell-model state of the target. But the reaction was assumed to have taken place by the pick-up of a preformed triton cluster (also bound in a shell-model state of the target core) by the incident proton for the pick-up mechanism. The Yukawa forms of potential were used for the proton-alpha (for the knock-on process) and proton-triton (for the pick-up process) interaction and several parameter sets for the proton and alpha-particle optical potentials. The calculated cross-sections for both mechanisms gave satisfactory fits to the experimental data. Furthermore, it has been shown that some combinations of the calculated distorted wave Born approximation cross-sections for the two reaction mechanisms in the FKK MSD theory are able to give better fits to the experimental data, especially in terms of range of agreement. In addition, the theory has been observed to be valid over a wider range of energy.

The Evaluation of Regional Innovation and Cluster Policies : Theory and Methods (지역혁신과 클러스터 정책의 평가: 이론과 방법)

  • Diez, Maria Angeles
    • Journal of the Korean Academic Society of Industrial Cluster
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    • v.1 no.1
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    • pp.1-15
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    • 2007
  • Regional innovation and cluster policies are the new agenda of regional policy, an agenda that began to spread over recent years throughout different countries and regions. In this context, our main question arises: how are we going to evaluate regional innovation and cluster policies? What models and methods are we going to use? Since 1990, regional and national governments have put more emphasis on evaluation as a tool directed to produce knowledge to design better policies. The objective of this article is to summarise the main challenges arising from the evaluation of regional innovation and cluster policies and make some methodological proposals that can contribute to produce better evaluations. In the first section, there is a brief presentation of regional innovation and cluster policies, followed by a more detailed analysis, in the second section, of their principal characteristics and of the main challenges posed by their evaluation. In the third section, some evaluation proposals that can help to improve current evaluation practice are presented. The paper concludes with a short number of general recommendations that we should bear in mind when designing an evaluation of regional innovation and cluster policies.

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