Lattices of Interval-Valued Fuzzy Subgroups

이정곤,허걸,임평기 한국지능시스템학회 2014 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.14 No.2

We discuss some interesting sublattices of interval-valued fuzzy subgroups. In our main result,we consider the set of all interval-valued fuzzy normal subgroups with finite range that attainthe same value at the identity element of the group. We then prove that this set forms a modularsublattice of the lattice of interval-valued fuzzy subgroups. In fact, this is an interval-valuedfuzzy version of a well-known result from classical lattice theory. Finally, we employ a latticediagram to exhibit the interrelationship among these sublattices.

시계열 거리 계산에서 미리 버림 효과의 최대화

이정곤,김상필,문양세,김진호 한국정보과학회 2011 데이타베이스 연구 Vol.27 No.2

In recent years, there have been many efforts on exploiting a large time‐series database, and their major research topic is similar sequence matching that identifies data sequences similar to a query sequence. In this paper, we address the problem of maximizing the early abandon effect in computing the Euclidean distances for similar sequence matching. The early abandon improves the matching performance by stopping the computation process immediately after the intermediate distance exceeds a user‐specified threshold value. We observe that the starting offset highly influences the early abandon effect, and we thus try to select the starting offset so as to maximize the early abandon effect. We first propose MaxOffset that uses the maximum entry of a query sequence as its starting offset. As an extension of MaxOffset, we then propose BiDirection that considers both directions of the maximum entry, i.e., left‐side adjacent entries as well as right‐side adjacent entries. The intuition behind these algorithms is that a large portion of the actual distance might be accumulated around maximum entries. We empirically showcase the superiority of the proposed algorithms. 최근 대용량의 시계열 데이터 처리 연구가 활발하게 진행되고 있다. 이러한 시계열 데이터 처리에서 주된 연구 분야인 유사 시퀀스 매칭은 주어진 질의 시계열과 유사한 데이터 시계열을 찾는 방법이다. 본 논문에서는 유사 시퀀스 매칭의 유사 척도로 유클리디안 거리을 다루며, 기존의 미리 버림 효과를 최대화하는 방안을제시한다. 미리 버림이란, 유클리디안 거리 계산 과정 중 중간 거리 값이 사용자가 정한 허용치보다 크면 나머지 거리 계산 과정을 생략하는 방법이다. 본 논문에서는 거리 계산의 시작 오프셋(위치)을 달리 함으로써 미리 버림 효과를 최대화하고 이를 통해 성능을 향상시키는 방안을 제시한다. 첫째, 질의 시계열의 최대값 엔트리를 시작 오프셋으로 하는 최대값 오프셋 기법을 제안한다. 이는 최대값 부근에서 질의와 데이터 시계열의 거리 차이가 클 것이라는 직관에 기반한다. 둘째, 최대값 오프셋 기법을 개선하여 최대값 오프셋에서 왼쪽 및 오른쪽의 양방향으로 거리를 계산해 가는 최대값 오프셋 양방향 기법을 제안한다. 이는 최대값 부근에서 발생하는 거리 차이를 가급적 많이 활용하고자 하는 직관에 기반한다. 마지막으로 실험을 통해 제안한 방법이 기존 방법에 비해 성능을 크게 향상시킨 것을 보인다.

Interval-Valued Fuzzy Congruences on a Semigroup

이정곤,허걸,임평기 한국지능시스템학회 2013 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.13 No.3

We introduce the concept of interval-valued fuzzy congruences on a semigroup S and we obtain some important results: First, for any interval-valued fuzzy congruence R on a group G, the interval-valued congruence class Re is an interval-valued fuzzy normal subgroup of G. Second, for any interval-valued fuzzy congruence R on a groupoid S, we show that a binary operation*an S/R is well-defined and also we obtain some results related to additional conditions for S. Also we improve that for any two interval-valued fuzzy congruences R and Q on a semigroup S such that R⊂Q, there exists a unique semigroup homomorphism g : S/R→S/G.

Cognitive Improvement through Breathing Exercises in Post-Stroke Respiratory Sarcopenia: A Review

이정곤,이재훈,하민성 한국운동생리학회 2023 운동과학 Vol.32 No.4

PURPOSE: The first purpose of this study is to investigate the relationship between Post-Stroke Respiratory Sarcopenia (PSRS) and Cognitive Impairment (CI) through Breathing Exercise (BE) as a respiratory rehabilitation after stroke (ST). The second purpose is to introduce a pilot study design set to investigate and compare the acute effects of each BE to develop a BE protocol for further studies. METHODS: Pubmed, Scopus, Web of Science and Google Scholar search engines were used to identify the definition and mechanism of ST, CI and respiratory sarcopenia (RS), and to find cases of application of BE in such conditions. RESULTS: Review; BEs that improve ST, RS, and CI symptoms are Box Breathing (Tactical Breathing), Fast-Breathing, Slow-paced Breathing, Inspiratory Diaphragmatic Breathing+Expiratory Pursed-lip Breathing Exercise. However, the effect is still unclear as post-stroke patients undergo multiple medical treatments other than BE. Pilot Study Prospective results; Inspiratory Diaphragmatic Breathing+Expiratory Pursed-lip Breathing Exercise, Slow-paced Breathing, Box Breathing (Tactical Breathing) and Fast-Breathing will be performed by 40 healthy college students through a randomized controlled trial for 4 weeks. Respiratory functions, exercise intensity, active oxygen level, blood lactate level, cerebral oxygen saturation and cognitive function will be measured pre- and post-intervention along with acute and 2 week mid-intervention. BEs are expected to improve respiratory function, cognitive performance and energy levels while reducing HR, BP, and stress. However, individual response to BE may vary according to health, physical fitness and life styles. All BE will be conducted in an evenly controlled and supervised environment for accurate data collection. CONCLUSIONS: Further study will be done to develop an appropriate BE protocol for PSRS patients per this review. Follow-up studies may also use this review as a reference for the application of BEs in PSRS patients with CI.

SOME CONVERGENCE PROPERTIES OF THE SIGNED GENERATED CHOQUET INTEGRAL

이정곤,장이채 장전수학회 2015 Proceedings of the Jangjeon mathematical society Vol.18 No.2

Couso-Montes-Gil (2002) proved some convergence theorems of the Choquet integral and Mihailovic-Pap (2011) studied the generated Choquet integral. In this paper, we consider the signed generated Choquet integral and investigate its properties. In particular, we define convergence in mean for the signed generated Choquet integral and discuss some convergence theorems for them.

Closures and Interiors Redefined, and Some Types of Compactness in Ordinary Smooth Topological Spaces

이정곤,임평기,허걸 한국지능시스템학회 2013 한국지능시스템학회논문지 Vol.23 No.1

We give a new definition of ordinary smooth closure and ordinary smooth interior of an ordinary subset in an ordinary smooth topological space which have almost all the properties of the corresponding operators in a classical topological space. As a consequence of these definitions we reduce the additional hypotheses in the results of [1] and also generalize several properties of the types of compactness in [1].

비전형적 대뇌 침범을 동반한 고혈압성 뇌간뇌병증 1예

이정곤,노학재,장일미,이경복,안무영 대한뇌졸중학회 2012 Journal of stroke Vol.14 No.3

Hypertensive brainstem encephalopathy (HBE) is a variant of hypertensive encephalopathy characterized by brainstem and cerebellar involvement. Simultaneous supratentorial involvement in HBE is rarely reported as a vasogenic edema in subcortex and/or periventricular white matter. A 36-year-old woman visited hospital due to headache lasting 7 days before admission. Initial blood pressure was 270/170mmHg. T2-weighted and fluid-attenuated inversion recovery magnetic resonance imaging revealed multifocal high signal intensity lesions in upper medulla, pons, midbrain and cerebellar hemisphere. Especially, atypical periventricular lesions were shown as perpendicular fingers to the lateral ventricle like multiple sclerosis. Her clinical symptoms and radiological lesions were subsided with lowering blood pressure. We herein report a HBE with unusual supratentorial involvement mimicking multiple sclerosis.

The stability of Hilbert space framelets and Riesz frames

이정곤,이동명 호남수학회 2005 호남수학학술지 Vol.27 No.4

We consider the stability of Hilbert space framelets and related Riesz frames. Our results are in spirit close to classical results for orthonormal bases, due to Mazur and Schauder.

Interval-valued Fuzzy Subgroups

이정곤,허걸,임평기 호남수학회 2013 호남수학학술지 Vol.35 No.4

We study the conditions under which a given interval-valued fuzzy subgroup of a given group can or can not be realized as a union of two interval-valued fuzzy proper subgroups. Moreover, we provide a simple necessary and sufficient condition for the union of an arbitrary family of interval-valued fuzzy subgroups to be an interval-valued fuzzy subgroup. Also we formulate the concept of interval-valued fuzzy subgroup generated by a given interval-valued fuzzy set by level subgroups. Furthermore we give characterizations of interval-valued fuzzy conjugate subgroups and interval-valued fuzzy characteristic subgroups by their level subgroups. Also we investigate the level subgroups of the homomorphic image of a given interval-valued fuzzy subgroup.

입얼굴이상운동으로 발현한 파르병

이정곤,김승주,장일미,이경복,노학재,안무영 대한신경과학회 2013 대한신경과학회지 Vol.31 No.1