A fabrication of low-power distribution systems for muon g - 2/EDM experiment at J-PARC

Won E.,Lee Woodo 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.79 No.3

A special DC-to-DC converter is designed to supply low-power to the detector system of the J-PARC g − 2/EDM experiment, which aims to measure the anomaly of the muon magnetic dipole moment, aμ = (g − 2)∕2 . The important requirement of the DC-to-DC converter is that the stray magnetic field from the converter should be less than 30 μT to reach the experimental sensitivity of 450 ppb. The DC-to-DC converter contains one buck converter and three regulators, featured with a customary designed air-core inductor. The detailed design and test results for the voltage stability, stray magnetic field, and heat dissipation in vacuum are reported.

A development of a compact software package for systematic error studies in muon g-2/EDM experiment at J-PARC

Won E.,Lee Woodo 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.79 No.3

The J-PARC muon g − 2/EDM experiment aims to measure the muon magnetic moment anomaly aμ = (g − 2)∕2 . The target sensitivity for aμ is a statistical uncertainty of 450 × 10−9 , and aμ can be extracted by measuring the spin precession of muons (ωa). The ωa can be extracted from the distribution of muon decay time, and the time is measured by reconstructing tracks of positrons that are decayed from the muons. To extract ωa precisely, the systematic effects on ωa should be controlled under the aforementioned sensitivity. To study systematic effects, we develop a compact simulation package, and using our developed package, we study several systematic effects and discuss the results. We discuss the implementation details of the package and studies of systematic effects on ωa.

Search for a dark vector gauge boson decaying toπ+π−usingη→π+π−γdecays

Won, E.,Adachi, I.,Aihara, H.,Al Said, S.,Asner, D. M.,Aushev, T.,Ayad, R.,Badhrees, I.,Bakich, A. M.,Bansal, V.,Barberio, E.,Behera, P.,Bhuyan, B.,Biswal, J.,Bobrov, A.,Bozek, A.,Brač,ko, M.,&#x American Physical Society 2016 Physical Review D Vol.94 No.9

<P>We report a search for a dark vector gauge boson U' that couples to quarks in the decay chain D*(+) -> D-0 pi(+), D-0 -> K-S(0) eta, eta -> U'gamma, U' -> pi(+)pi- No signal is found and we set a mass-dependent limit on the baryonic fine structure constant of 10(-3)-10(-2) in the U' mass range of 290 to 520 MeV/c(2). This analysis is based on a data sample of 976 fb(-1) collected by the Belle experiment at the KEKB asymmetric-energy e(+)e(-) collider.</P>

Measurement ofD+→KS0K+andDs+→KS0π+branching ratios

Won, E.,Ko, B. R.,Aihara, H.,Arinstein, K.,Aulchenko, V.,Aushev, T.,Bakich, A. M.,Balagura, V.,Barberio, E.,Bay, A.,Belous, K.,Bhardwaj, V.,Bischofberger, M.,Bondar, A.,Bozek, A.,Brač,ko, M.,Brow American Physical Society 2009 PHYSICAL REVIEW D - Vol.80 No.11

Development of track segment finder for central drift chamber based level-1 trigger system in the Belle II experiment

Won E.,Kim K. T. 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.78 No.9

The Belle II experiment is constructed at the KEK High Energy Accelerator Research Organization in Japan. Due to the high luminosity of the beam, a trigger that effectively rejects beam-induced background is required. For this purpose, a level-1 trigger board with field-programmable gate arrays and high speed optical transceivers is developed for the central drift chamber trigger readout. Utilizing this hardware, we develop our algorithms, which find segments of charged particle trajectories using information of the central drift chamber.

Cu₃Au(100)와 Ni₃Pt(100)의 표면 질서와 표면 편석

韓源根,徐芝根 弘益大學校 科學技術硏究所 1996 科學技術硏究論文集 Vol.7 No.1

We simulate the thermodynamic behavior of Cu₃Au(100) and Ni₃Pt(100) surfaces, focusing on the segregation and ordering. Through Monte Carlo simulations of a short-range Ising model Hamiltonian, we can explain the surface segregation on a quantitative level in good agreement with previous experimental observation. Further we reveal that Cu₃Au(100) shows a surface-induced disordering behavior as suggested in previous works and Ni₃Pt(100) would show a surface-induced ordering though both system show a very similar phase transition and surface segregation.

企業의 不實豫測模形에 관한 硏究

李原均 慶一大學校 1993 論文集 Vol.9 No.1

Early warning system for business failure prediction will be helpful to many interest groups of a firm. Business failure prdiction is a case of binary classification in which the number of groups is limited to two. Numerous methods have been developed for classification purpose. They are typically referred to a multivariate discriminant analysis(MDA). Thereafter, Logit analysis and Probit analysis are developed for failure prediction. These models are not deterministics but stochastic. In the current study, neural network approach is developed as a tool to discriminate business failure. The purpose of this paper is to review the models in business failure prediction and verify the posibilities and limitations of neural net model as a classification tool.

A new method of surface dynamics

韓源根 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.5 No.-

We developed a new method of studying surface dynamics of metal surfaces by combining the analytic and simulational methods. In this formalism, the vibrational motion of bulk atoms are considered to be harmonic using a central force model, however, that of surface atoms is considered to be anharmonic in order to explain the surface structural change. We show that the dynamical structure factor can be expressed as a continued fraction and its expansion parameters are equilibrium thermodynamic averages, which can be evaluated through Monte Carlo simulation. Therefore, we conclude that the static behaviors and surface dynamics which are anhamonic and critical can be studied more systematically at the same time.

企業의 財務報告에 대한 데이타베이스 公示(database disclosure)의 實行可能性에 관한 硏究

李源均 慶一大學校 1990 論文集 Vol.6 No.1

Sorter's proposal for events-observation approach to accounting theory provides a basis for database approach. A fundmental difference between events approach and value-inference approach lies in the definition of relevant economic events. The essence of the events approach to accounting theory is that relevant economic events, rather than financial statements, should be the primary units of corporate financial reporting. The economic events without aggregation and valuation are reported to users. The users aggregate and value the events with their own choice. Under value theory, economic events associated with a particular reporting entity are observed, recored, aggregated, assigned values, and after then reported by accountants of the entity to information users. Recently US. SEC developed EDGAR(Electronic Data Gathering Analysis and Retrival) program, which indicates that financial reporting may be evolving toward a database disclosure. This paper examines the technical and economic feasibility of database disclosure. Now a days, the technical feasibility is approximately achieved with the advanced computer and communication technology. But the database disclosure would have varing economic effects on participants group in our economy. The most vocal advocates of database disclosure are expected to be government regulators(monitoring and enforcing regulations), accounting scholars, data processing industry, and average investors(not having private information). The most vocal opponents of database disclosure are expected to be corporate managers, corporate accountants, and investors with private information. Sooner or later, the database disclosure for financial reporting will change accounting environment. I wish newly developed accounting disclosure system, like EDGAR, shall be implemented in Korea.

PtNi(110)에서 표면편석과 질서 - 무질서

韓源根,徐芝根 弘益大學校 科學技術硏究所 1993 科學技術硏究論文集 Vol.3 No.-

PtNi(110) 합금에서의 표면 편석 현상과 질서-무질서 상전이 현상을 몬테 카를로 시뮬레이션 방법을 통하여 고찰하였다. 간단한 Ising 모델로 PtNi 합금의 질서 무질서 상전이 현상을 잘 보여줄 수 있었고, 실험에서 관측된 (110)표면에서 나타나는 편석 역전 현상, 그리고 편석되는 정도, 층별 농도 분포를 양적으로도 잘 설명할 수 있었다. 치환형 합금에서 편석은 표면과 bulk 사이의 질서 차이로 발현됨을 보았고, 편석량도 이 질서 현상에 깊게 의존하는 것을 보았다. 질서-무질서 상전이를 표면 편석과 동시에 고려함으로서 이 두가지 현상이 보다 완전히 이해될 수 있음을 보였다. We investigated the surface segregation and order-disorder phase transition on PtNi(110) alloy through Monte Carlo simulation. We reproduced the order-disorder phase transition with a simple Ising model and explained the segregation reversal, amount of segregation, and concentration depth profile as observed on its (110) surface on a good quantitative level. We demonstrated that the segregation in a substitutional alloy appeared due to the difference between the degree of order of a bulk and that of the surface and the amount of segregation also depends on the degree of order. We finally showed that the order-disorder phase transition and the surface segregation are to be considered at the same time for a better understanding.