• East Asian mathematical journal
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• v.21 no.2
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• pp.205-217
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• 2005

In this paper we consider the fuzzy ideals of N-group G where N is a near-ring. We introduce the concepts: minimal elements, fuzzy linearly independent elements, and fuzzy basis of an N-group G and obtained fundamental related results.

• Journal for History of Mathematics
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• v.1 no.1
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• pp.14-32
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• 1984

The concepts of zero, minus, infinite, ideal point, etc. are not real existence, but are pure mathematical objects. These entities become mathematical objects through the process of a philosophical filtering. In this paper, the writer explores the relation between natural conditions of different cultures and philosophies, with its reference to fundamental philosophies and traditional mathematical patterns in major cultural zones. The main items treated in this paper are as follows: 1. Greek ontology and Euclidean geometry. 2. Chinese agnosticism and the concept of minus in the equations. 3. Transcendence in Hebrews and the concept of infinite in modern analysis. 4. The empty and zero in India.

• Journal of the Korean Mathematical Society
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• v.49 no.4
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• pp.703-713
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• 2012

In this paper we study ${\omega}$-limit sets and attraction of non-autonomous discrete dynamical systems. We introduce some basic concepts such as ${\omega}$-limit set and attraction for non-autonomous discrete system. We study fundamental properties of ${\omega}$-limit sets and discuss the relationship between ${\omega}$-limit sets and attraction for non-autonomous discrete dynamical systems.

• Journal for History of Mathematics
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• v.36 no.2
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• pp.21-34
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• 2023

Spherical trigonometry refers to the geometry related to spherical triangles. It has been an important tool for studying astronomy since ancient times. In trigonometry, concepts such as trigonometric functions naturally emerge from the relationship between arcs and chords of a circle. In this paper, we briefly examine the origin of spherical trigonometry. To introduce the basics of spherical trigonometry, we present fundamental and important theorems such as Menelaus's theorem, the law of sines and the law of cosines on a sphere, along with their proofs. Furthermore, we discuss the educational value and potential applications of spherical trigonometry.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.1
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• pp.59-72
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• 2014

This study investigated slow fashion consumers from a human desire viewpoint in order to examine the psychological aspects of slow fashion consumption. First, the concept of slow fashion was defined. Second, this study reviewed the concepts of desire found in Oriental philosophies and applied them to slow fashion consumption. This process identified the fundamental desire that motivates consumers of slow fashion. Lastly, the psychological aspects slow fashion consumers were examined through a comparison of fundamental desire and external reasons given by interviewees in regards to personal motivation to purchase slow fashion products. Data were collected through in-depth interviews with 10 unmarried women 25 to 37 years old with experience in buying slow fashion products. Exploratory data were classified into external reasons and fundamental reasons to derive the concept of slow fashion. First, slow fashion is defined as sustainable fashion that considers humans and nature. It also seeks to produce morally good products that transcend time and space. Second, we identified the following external reasons: social responsibility, pursuit of healthy products, and pursuit of beauty. Finally, we extracted four factors that reflected fundamental desire: Recognition Desire, Ostentation Desire, Sexual Appeal Desire, and Power Desire. Altruism was emphasized by respondents who expressed social responsibility among external reasons and the desire for recognition among fundamental reasons. However, this goodwill also originated from human desire due to the emotional healing they receive from helping others. Interviewees sought psychological benefits such as self-satisfaction and spiritual growth through slow fashion that implied an Association of slow fashion consumption with human desire. Slow fashion consumption was influenced by moral convictions as well as various desires; in addition, external reasons for slow fashion consumption could be explained by desire.

• Nuclear Engineering and Technology
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• v.37 no.5
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• pp.401-422
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• 2005

We review here research and development progress achieved in US Plasma Chamber technology roughly over the last decade. In particular, we focus on two major programs carried out in the US: the APEX project (1998-2003) and the US ITER TBM activities (2003-present). The APEX project grew out of the US fusion program emphasis in the late 1990s on more fundamental science and innovation. APEX was commissioned to investigate novel technology concepts for achieving high power density and high temperature reactor coolants. In particular, the idea of liquid walls and the related research is described here, with some detailed examples of liquid metal and molten salt magnetohydrodynamic and free surface effects on flow control and heat transfer. The ongoing US ITER Test Blanket Module (TBM) program is also described, where the current first wall/blanket concepts being considered are the dual coolant lead lithium concept and the solid breeder helium cooled concepts, both using ferritic steel structures. The research described for these concepts includes both thermofluid MHD issues for the liquid metal coolant in the DCLL, and thermomechanical issues for ceramic breeder packed pebble beds in the solid breeder concept. Finally, future directions for ongoing research in these areas are described.

• Journal of Oriental Neuropsychiatry
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• v.11 no.1
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• pp.103-113
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• 2000

The aim of this study is to review the concepts of Jing(精) Qi(氣) Shen(神) Hun(魂) Po(魄) in the light of the Jungian psychology. According to the explanations of the Jungian psychology human beings have archetypes-a priori conditioning factors-in the collective unconscious. These archetyps are concerned with common concepts conceived by mankind about the fundamental elements which constitute the universe and the existence. The archetype is perceived in a symbol, hence Jing(精) Qi(氣) Shen(神) Hun(魂) Po(魄) also are these symbolic representations which had common background of mankind. The meaning of Jing(精) is emphasized as psychic and physical elements, and concerned with instinct. Qi(氣) corresponds to Jung's definition of libido as life energy. The concept of Shen(神) has the value of the self archetype as whole psyche's president principle. Hun(魂) and Po(魄) are intuitive notions of the Orient compared with Animus and Anima which are characteristic representations. However from a standpoint of autonomous energy as archetype the difference would be diminished. Considering each purpose of Hun(魂) and Po(魄) Hun(魂) has a intention of integrating the unconscious flux into consciousness while Po(魄) has a tendency toward instinct to secure a body. It is precious to recognize deeply that these concepts of jing(精) Qi(氣) Shen(神) Hun(魂) Po(魄) play an important part which mediate between the unconscious and consciousness, psyche and body as symbols.

• Journal of the Korean Society for Library and Information Science
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• v.8
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• pp.73-101
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• 1981

Retrieval effectiveness is the principal criterion for measuring the performance of an information retrieval system. The effectiveness of a retrieval system depends primarily on the extent to which it can retrieve wanted documents without retrieving unwanted ones. So, ultimately, effectiveness is a function of the relevant and nonrelevant documents retrieved. Consequently, 'relevance' of information to the user's request has become one of the most fundamental concept encountered in the theory of information retrieval. Although there is at present no consensus as to how this notion should be defined, relevance has been widely used as a meaningful quantity and an adequate criterion for measures of the evaluation of retrieval effectiveness. The recall and precision among various parameters based on the 'two-by-two' table (or, contingency table) were major considerations in this paper, because it is assumed that recall and precision are sufficient for the measurement of effectiveness. Accordingly, different concepts of 'relevance' and 'pertinence' of documents to user requests and their proper usages were investigated even though the two terms have unfortunately been used rather loosely in the literature. In addition, a number of variables affecting the recall and precision values were discussed. Some conclusions derived from this study are as follows: Any notion of retrieval effectiveness is based on 'relevance' which itself is extremely difficult to define. Recall and precision are valuable concepts in the study of any information retrieval system. They are, however, not the only criteria by which a system may be judged. The recall-precision curve represents the average performance of any given system, and this may vary quite considerably in particular situations. Therefore, it is possible to some extent to vary the indexing policy, the indexing policy, the indexing language, or the search methodology to improve the performance of the system in terms of recall and precision. The 'inverse relationship' between average recall and precision could be accepted as the 'fundamental law of retrieval', and it should certainly be used as an aid to evaluation. Finally, there is a limit to the performance(in terms of effectiveness) achievable by an information retrieval system. That is : "Perfect retrieval is impossible."

• Tunnel and Underground Space
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• v.30 no.6
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• pp.591-602
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• 2020

Several alternative rock-cutting concepts, which are modified from the conventional ones, have been developed lately. Of the concepts, undercutting is one of the latest technologies. In this study, as a fundamental study on the undercutting technique, the rock-cutting mechanism and important parameters of the undercutting were introduced. This study built up cutting test system for evaluating the cutting performance of an actuated undercutting disc cutter (ADC), and carried out a series of cutting tests under different cutting parameters of ADC. The characteristics of cutter forces obtained from ADC rock-cutting tests were analyzed. The both average and peak values of the three directional cutter forces were linearly increased with the increases of linear velocity, penetration depth in vertical direction and eccentricity of ADC.

• Communications of Mathematical Education
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• v.37 no.4
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• pp.635-652
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• 2023

This study conducts a comprehensive analysis of the curricular progression of the concepts and learning sequences of 'lines', specifically, 'line segments', 'straight lines', and 'rays', at the elementary school level. By examining mathematics curricula and textbooks, spanning from 2nd to 7th and 2007, 2009, 2015, and up to 2022 revised version, the study investigates the timing and methods of introducing these essential geometric concepts. It also explores the sequential delivery of instruction and the key focal points of pedagogy. Through the analysis of shifts in the timing and definitions, it becomes evident that these concepts of lines have predominantly been integrated as integral components of two-dimensional plane figures. This includes their role in defining the sides of polygons and the angles formed by lines. This perspective underscores the importance of providing ample opportunities for students to explore these basic geometric entities. Furthermore, the definitions of line segments, straight lines, and rays, their interrelations with points, and the relationships established between different types of lines significantly influence the development of these core concepts. Lastly, the study emphasizes the significance of introducing fundamental mathematical concepts, such as the notion of straight lines as the shortest distance in line segments and the concept of lines extending infinitely (infiniteness) in straight lines and rays. These ideas serve as foundational elements of mathematical thinking, emphasizing the necessity for students to grasp concretely these concepts through visualization and experiences in their daily surroundings. This progression aligns with a shift towards the comprehension of Euclidean geometry. This research suggests a comprehensive reassessment of how line concepts are introduced and taught, with a particular focus on connecting real-life exploratory experiences to the foundational principles of geometry, thereby enhancing the quality of mathematics education.