• 대한수학회보
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• 제46권5호
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• pp.823-833
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• 2009

It is well-known that if a convex hyperbolic polygon is constructed as a fundamental domain for a subgroup of the modular group, then its translates by the group elements form a locally finite tessellation and its side-pairing transformations form a system of generators for the group. Such hyperbolically convex polygons can be obtained by using Dirichlet's and Ford's polygon constructions. Another method of obtaining a fundamental domain for subgroups of the modular group is through the use of a right coset decomposition and we call such domains standard fundamental domains. In this paper we give subgroups of the modular group which do not have hyperbolically convex standard fundamental domain containing only inequivalent cusps.

• 대한수학회지
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• 제45권4호
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• pp.1007-1025
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• 2008

We will describe a way to construct Ford domains of cusped hyperbolic 3-manifolds on maximal cusp diagrams and compute fundamental groups using face pairing maps as generators and Cannon-Floyd-Parry's edge cycles as relations. We also describe explicitly a cutting and pasting alteration to reduce the number of faces on the bottom region of Ford domains. We expect that our analysis of Ford domains will be useful on other future research.

• 대한전자공학회논문지SP
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• 제47권5호
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• pp.100-108
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• 2010

본 논문은 피치를 추출하는 방법으로 자기상관을 이용하였다. 시간과 주파수 영역의 자기상관은 서로 다른 특성을 가지고 있으며, 각각 피치주기와 기본주파수에 대응된다. 본 논문에서는 시간과 주파수 영역에서의 자기상관을 결합하는 방법을 이용하였다. 이 방법은 자기상관에서 발생하는 피치 doubling과 having 에러를 크게 개선시킬 수 있었다. 하지만, 시간과 주파수 영역에서 유성음의 주기적 특성인 피치주기와 기본주파수는 서로 역수 관계이며, 특히 기본주파수의 에러는 FFT의 분해능에 의하여 발생된다. 이러한 영향을 줄이기 위하여 시간 영역과 주파수 영역에서의 자기상관 결합에 보간법을 적용함으로써 피치 검출율을 향상 시킬 수 있었다. 자기상관을 결합할 때 시간영역에서 찾은 피치후보들에 대해서만 주파수영역의 자기상관을 구함으로써 계산량은 감축될 수 있었다. 또한, 선형보간을 이용하여 기존방법 보다 FFT 계수를 8배 줄일 수 있었다. 그 결과, FFT 연산량과 주파수영역의 자기상관 계산량을 크게 감축하여 기존 방법 대비 알고리즘 처리시간을 약 9.5배 줄일 수 있었다.

• Asia pacific journal of information systems
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• 제34권1호
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• pp.49-90
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• 2024

Intradisciplinary research refers to research that integrates ideas often associated with different research domains in a discipline. Such cross-fertilization leverages abundant diversity present in the IS discipline to tackle increasingly complex IS problems and grand challenges. Despite its importance and recent attention, a concerted, sustained effort toward intradisciplinary research is lagging. A fundamental issue we see is a lack of an elaborate IS research map that effectively shows similarities and differences among research domains and demonstrates types of ideas that may travel and integrate into different domains. We thus aim to propose an elaborate IS research map and compile research elements that can be tried and combined across research domains. To do so, we utilize two IS classics (i.e., IT views and IS phenomena), identify their complementarity, and interweave the two disparate ways of portraying the IS research field. The resultant view-phenomenon (VP) matrix specifies research domains based on two consistent, comprehensive criteria and helps researchers discern similarities and differences among research domains more effectively. The VP matrix also sheds light on a variety of research elements that can flow across research domains. The VP matrix along with the research elements together facilitate intradisciplinary efforts and, more broadly, help the IS discipline to prosper. The VP matrix is particularly helpful for doctoral students and young scholars.

• Agricultural and Biosystems Engineering
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• 제2권1호
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• pp.15-23
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• 2001

On the assumption that the voices of the cows are produced by the linear prediction filter, we characterized the cows’voices. The order of this filter was determined by examining the voice characteristics both in time and frequency domains. The proposed order of the linear prediction filter is 15 for modeling voice production of the cow. The characteristics of the amplitude envelope of the voice signal was investigated by analyzing the sequence of the short time variance both in time and frequency domains, and the new parameters were defined. One of the coefficients o the linear prediction filter generating the voice signal, the fundamental frequency, the slope of the straight line regressed from the log-log spectra of the short time variance and the coefficients of the linear prediction filter generating the sequence of the short time variance of the voice signal can differentiate the two cows.

• Korean Journal of Mathematics
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• 제30권2호
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• pp.315-333
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• 2022

We give a general procedure to analyze the structure for certain ℂ-Fuchsian subgroups of some non-arithmetic lattices. We also show their presentations and describe their fundamental domains which lie in a complex geodesic, a set homeomorphic to the unit disk.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권10호
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• pp.2692-2707
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• 2012

A separable identity-based ring signature scheme has been constructed as a fundamental cryptographic primitive for protecting user privacy. Using the separability property, ring members can be selected from arbitrary domains, thereby, giving a signer a wide range of ways to control privacy. In this paper we propose a generic method to construct efficient identity-based ring signature schemes with various levels of separability. We first describe a method to efficiently construct an identity-based ring signature scheme for a single domain, in which a signer can select ring identities by choosing from identities defined only for the domain. Next, we present a generic method for linking ring signatures constructed for a single domain. Using this method, an identity-based ring signature scheme with a compact structure, supporting multiple arbitrary domains can be designed. We show that our method outperforms the best known schemes in terms of signature size and computational costs, and that the security model based on the separability of identity-based ring signatures, presented in this paper, is highly refined and effective by demonstrating the security of all of the proposed schemes, using a model with random oracles.

• 기본간호학회지
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• 제25권1호
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• pp.33-45
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• 2018

Purpose: Objectives of this study were to identify and describe cultural meaning for nursing students in the class in fundamental nursing practice. Methods: Data were collected from November 2016 to May 2017 included focus group interviews and participants observation. The key informants in this study included 23 nursing students divided into 3 focus groups who had taken the course in fundamental nursing practice in university U and university S in Kyungpook, and university D in Jeonnam. Interviews continued until no new information could be identified from transcripts. Data were analyzed using the taxonomic analysis method developed by Spradley. Results: Based on the data acquired from the interviews, cultural domains in the class "fundamental nursing practice" were classified as 'community oriented activities', 'learning and playing space', 'relationship of difference and discrimination', 'time for present and future'. Conclusion: The culture in the class "fundamental nursing practice" could be summarized as 'non-standardized learning with team dynamics'. Also nursing students learned about a small society whose members are becoming nurses. Results indicate that it is critical for professors to understand students' values, beliefs and their attitude in order to aid in adjustment to class.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.196-203
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• 2000

On the assumption that the voices of the cows are produced by the linear prediction filter, we characterized the cows' voices. The order of this filter is determined by examining the voices characteristics both in time and frequency domains. The proposed order of the linear prediction filter is 15 for modeling voice production of the cow. The combination of the two parameters of the fundamental frequency, the slope of the straight line regressed from the log-log spectra of the amplitude-envelope and the only one coefficient involved in the linear prediction filter can differentiate the two cows.

• 대한수학회지
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• 제54권1호
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• pp.303-317
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• 2017

An isometry of hyperbolic space can be written as a composition of the reflection in the isometric sphere and two Euclidean isometries on the boundary at infinity. The isometric sphere is also used to construct the Ford fundamental domains for the action of discrete groups of isometries. In this paper, we study the isometric spheres of isometries acting on hyperbolic 4-space. This is a new phenomenon which occurs in hyperbolic 4-space that the two isometric spheres of a parabolic isometry can intersect transversally. We provide one geometric way to classify isometries of hyperbolic 4-space using the isometric spheres.