Network topology and resilience analysis of South Korean power grid

Kim, Dong Hwan,Eisenberg, Daniel A.,Chun, Yeong Han,Park, Jeryang Elsevier 2017 PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIO Vol.465 No.-

<P><B>Abstract</B></P> <P>In this work, we present topological and resilience analyses of the South Korean power grid (KPG) with a broad voltage level. While topological analysis of KPG only with high-voltage infrastructure shows an exponential degree distribution, providing another empirical evidence of power grid topology, the inclusion of low voltage components generates a distribution with a larger variance and a smaller average degree. This result suggests that the topology of a power grid may converge to a highly skewed degree distribution if more low-voltage data is considered. Moreover, when compared to ER random and BA scale-free networks, the KPG has a lower efficiency and a higher clustering coefficient, implying that highly clustered structure does not necessarily guarantee a functional efficiency of a network. Error and attack tolerance analysis, evaluated with efficiency, indicate that the KPG is more vulnerable to random or degree-based attacks than betweenness-based intentional attack. Cascading failure analysis with recovery mechanism demonstrates that resilience of the network depends on both tolerance capacity and recovery initiation time. Also, when the two factors are fixed, the KPG is most vulnerable among the three networks. Based on our analysis, we propose that the topology of power grids should be designed so the loads are homogeneously distributed, or functional hubs and their neighbors have high tolerance capacity to enhance resilience.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Detailed information on power grid may produce highly-skewed degree distribution. </LI> <LI> Resilience of KPG is analyzed with multiple approaches including recovery. </LI> <LI> KPG is revealed as most vulnerable compared to ER and BA networks. </LI> </UL> </P>

Is There a "Trial Effect" on Outcome of Patients with Metastatic Renal Cell Carcinoma Treated with Sunitinib?

Daniel Keizman,Keren Rouvinov,Avishay Sella,Maya Gottfried,Natalie Maimon,Jenny J. Kim,Mario A. Eisenberger,Victoria Sinibaldi,Avivit Peer,Michael A. Carducci,Wilmosh Mermershtain,Raya Leibowitz-amit 대한암학회 2016 Cancer Research and Treatment Vol.48 No.1

Purpose Studies suggested the existence of a ‘trial effect,’ in which for a given treatment, participa- tion in a clinical trial is associated with a better outcome. Sunitinib is a standard treatment for metastatic renal cell carcinoma (mRCC). We aimed to study the effect of clinical trial participation on the outcome of mRCC patients treated with sunitinib, which at present, is poorly defined. Materials and Methods The records of mRCC patients treated with sunitinib between 2004-2013 in 7 centers across 2 countries were reviewed. We compared the response rate (RR), progression free survival (PFS), and overall survival (OS), between clinical trial participants (n=49) and a matched cohort of non-participants (n=49) who received standard therapy. Each clinical trial participant was individually matched with a non-participant by clinicopathologic factors. PFS and OS were determined by Cox regression. Results The groups were matched by age (median, 64), sex (male, 67%), Heng risk (favorable, 25%; intermediate, 59%; poor, 16%), prior nephrectomy (92%), RCC histology (clear cell 86%), pre-treatment neutrophil to lymphocyte ratio (> 3 in 55%, n=27), sunitinib induced hyper- tension (45%), and sunitinib dose reduction/treatment interruption (41%). In clinical trial participants versus non-participants, RR was partial response/stable disease 80% (n=39) versus 74% (n=36), and progressive disease 20% (n=10) versus 26% (n=13) (p=0.63; odds ratio, 1.2). The median PFS was 10 versus 11 months (hazard ratio [HR], 0.96; p=0.84), and the median OS 23 versus 24 months (HR, 0.97; p=0.89). Conclusion In mRCC patients treated with sunitinib, the outcome of clinical trial participants was similar to that of non-participants who received standard therapy.

카르복시 폴리술폰 아이오노머의 기계적 성질

유지강,이용혁,김희석,김준섭,박기주,D. Nguyen,A. Eisenberg 조선대학교 생산기술연구소 1997 生産技術硏究 Vol.19 No.1

The dynamic mechanical properties of carboxylated polysulfone ionomers were studied by using DMTA. It was found that at 25 mol% of ions, the ionomer shows two glass transitions: one at ca. 200 ℃ and the other at ca. 235 ℃. It was also found that with increasing an ion content to ca. 37 mol%, a matrix T_(g) shifts to ca. 210 ℃, but a cluster T_(g) remains at the same temperature; however, the sizes of tan δ peaks for each transitions do not change with the ion content. This result means that even at those high ion contents, there is sufficient amount of a unclustered material in the samples, and the increase in the ion content does not increase the volume fraction of a cluster phase. In addition, the difference in two T_(g)s of this ionomer system was found to be ca. 40 ℃, which is smaller than that in poly(styrene-co-methacrylate) ionomer system. This finding implies that in the polysulfone ionomers weak ionic interactions in a multiplet resulting from steric hindrance due to the bulkiness of benzene ring to which the ionic group is attached and the tension on polymer chains surrounding the multiplet due to chain rigidity affect the size and stability of the multiplet significantly.

CORPORATE GOVERNANCE : THE BOARD OF DIRECTORS AND INTERNAL CONTROL

Eisenberg, Melvin A. 東國大學校 大學院 法學科 商事法 2000 商事法 세미나 Vol.9 No.-

공개회사에 있어 이사회의 감독 및 정책결정기능을 의미롭게 하기 위해서는 내부통제에 대한 긍극적 책임이 이사회에게 집중되어야 한다. 이러한 책임을 이사회에 부과하는 것은 새로운 회사의 제도창출을 요하지 않는다. 다수의, 그리고 아마도 거의 대부분의 공개회사들에게 있어서 위와 같은 책임을 수행하기위해 필요한 요소들은 이미 존재하고 있다. 대신에, 주로 요구되어 지는 것은 내부통제에 대한 책임이 명백하여야 한다는 것, 이러한 책임의 의미가 구체화되어야 한다는 것, 그리고 이사회와 내부감사업무 사이에 적절한 연계가 있어야 한다는 것 등이다.

Sociotechnical Network Analysis for Power Grid Resilience in South Korea

Eisenberg, Daniel A.,Park, Jeryang,Seager, Thomas P. Hindawi Limited 2017 Complexity Vol.2017 No.-

<P>International efforts to improve power grid resilience mostly focus on technological solutions to reduce the probability of losses by designing hardened, automated, redundant, and smart systems. However, how well a system recovers from failures depends on policies and protocols for human and organizational coordination that must be considered alongside technological analyses. In this work, we develop a sociotechnical network analysis that considers technological and human systems together to support improved blackout response. We construct corresponding infrastructure and social network models for the Korean power grid and analyze them with betweenness to identify critical infrastructures and emergency management organizations. Power grid network analysis reveals important power companies and emergency management headquarters for responding to infrastructure losses, where social network analysis reveals how information-sharing and decision-making authority shifts among these organizations. We find that separate analyses provide relevant yet incomplete recommendations for improving blackout management protocols. In contrast, combined results recommend explicit ways to improve response by connecting key owner, operator, and emergency management organizations with the Ministry of Trade, Industry, and Energy. Findings demonstrate that both technological and social analyses provide important information for power grid resilience, and their combination is necessary to avoid unintended consequences for future blackout events.</P>

The Relationship between Neonatal Circumcision, Urinary Tract Infection, and Health

Michael L Eisenberg,Deron Galusha,William A. Kennedy,Mark R. Cullen 대한남성과학회 2018 The World Journal of Men's Health Vol.36 No.3

The risk-benefit profile of neonatal circumcision is not clear. Most studies have focused on urinary tract infections but other health sequelae have not been evaluated. While evidence supports benefits of circumcision, a lack of randomized trials has been cited as a weakness. National guidelines provide mixed recommendations regarding neonatal circumcision. We review the weight of evidence and utilize current statistical methodology on observational data to examine the risks and benefits of neonatal circumcision.

Role of myoferlin in regulation of cancer invasion

Yangjin Kim,Marisa C. Eisenberg,Ruth Li,William E. Ackerman,Douglas A. Kniss,Avner Friedman 한국산업응용수학회 2013 한국산업응용수학회 학술대회 논문집 Vol.8 No.1

Probing the Electron Accepting Orbitals of Ni-Centered Hydrogen Evolution Catalysts with Noninnocent Ligands by Ni L-Edge and S K-Edge X-ray Absorption

Koroidov, Sergey,Hong, Kiryong,Kjaer, Kasper S.,Li, Lin,Kunnus, Kristjan,Reinhard, Marco,Hartsock, Robert W.,Amit, Das,Eisenberg, Richard,Pemmaraju, C. Das,Gaffney, Kelly J.,Cordones, Amy A. American Chemical Society 2018 Inorganic Chemistry Vol.57 No.21

<P>The valence electronic structure of several square planar Ni-centered complexes, previously shown to catalyze the hydrogen evolution reaction, are characterized using S K-edge and Ni L-edge X-ray absorption spectroscopy and electronic structure calculations. Measurement of the atomic Ni 3d and S 3p contributions enables assessment of the metal-ligand covalency of the electron accepting valence orbitals and yields insight into the ligand-dependent reaction mechanisms proposed for the catalysts. The electron accepting orbital of the Ni(abt)<SUB>2</SUB> (abt = 2-aminobenzenethiolate) catalyst is found to have large ligand character (80%), with only 9% S 3p (per S) character, indicating delocalization over the entire abt ligand. Upon two proton-coupled reductions to form the Ni(abt-H)<SUB>2</SUB> intermediate, the catalyst stores 1.8 electrons on the abt ligand, and the ligand N atoms are protonated, thus supporting its role as an electron and proton reservoir. The electron accepting orbitals of the Ni(abt-H)<SUB>2</SUB> intermediate and Ni(mpo)<SUB>2</SUB> (mpo = 2-mercaptopyridyl-<I>N</I>-oxide) catalyst are found to have considerably larger Ni 3d (46-47%) and S 3p (17-18% per S) character, consistent with an orbital localized on the metal-ligand bonds. This finding supports the possibility of metal-based chemistry, resulting in Ni-H bond formation for the reduced Ni(abt-H)<SUB>2</SUB> intermediate and Ni(mpo)<SUB>2</SUB> catalyst, a critical reaction intermediate in H<SUB>2</SUB> generation.</P><P>The electronic structure of Ni-centered hydrogen evolution catalysts with noninnocent ligands was characterized using S and Ni edge X-ray absorption spectroscopies. The electron-accepting valence orbitals involved in catalysis are found to have high (>50%) ligand character. Ligand-dependent differences in electronic structure provide insight into the previously proposed reaction mechanisms of the catalysts.</P> [FIG OMISSION]</BR>