• Title/Summary/Keyword: Critical point theory

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Theory of Liquid Water (액체 물에 관한 이론)

  • Pak Hyungsuk
    • Journal of the Korean Chemical Society
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    • v.20 no.6
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    • pp.460-468
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    • 1976
  • A theory of liquid water is developed by assuming that the molecules in the liquid state have solid-like and gas-like degrees of freedom. The spectroscopic data are used in assigning the vibrational frequencies of solid-like molecules. The calculated values of molar volume, vapor pressure, entropy, entropy of vaporization, expansion coefficient, compressibility, heat capacities at constant volume and at constant pressure, surface tension and critical point properties are all in excellent agreement with the observed data.

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Operating Characteristics of a Bubble Pump for Diffusion-Absorption Refrigerator (확산형 흡수식 냉동기용 기포펌프의 운전특성에 관한 연구)

  • 이현경;김선창;이재헌
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.9
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    • pp.878-887
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    • 2001
  • Experimental investigation has been carried out to examine the operating characteristics of a bubble pump for diffusion absorption refrigerator. The effects of heat input and delivery height on generation rate of refrigerant vapor and circulation rate of solution have been investigated. as a result heat input and delivery height increase, circulation rate of solution increases. And the smaller the tube diameter, the larger the circulation rate of solution. Pumping ratio increases to a critical point and then decrease with the increase of heat input, and it increases with the increase in delivery height. In this paper, Marcus's analytical theory was also examined. It was found that the Marcus\`s analytical theory of a bubble pump was not appropriate for a bubble pump using ammonia aqueous solution as a working fluid.

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Natural Epistemic Attitude of Scientific Observation (과학적 관찰에 대한 자연스러운 인식적 태도)

  • Rhee Young-Eui
    • Journal of Science and Technology Studies
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    • v.1 no.1 s.1
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    • pp.155-178
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    • 2001
  • As is well known, logical positivists held the theory-independent of observation thesis(TIOT). On the other hand, the theories following the logical positivism typically represented by Hanson and Kuhn denied that there was a clear borderline between observation and theory, and held the theory-ladenness of observation thesis(TLOT). In order to mediate those theses I shall suggest a natural epistemic attitude (NEA) to the relation between theory and observation on the basis of the experimentalism. First, I discuss theories of Hanson and Kuhn as examples of views which profess TLOT. Then, I make a brief introduction of experimentalism and some critical discussions about TLOT follow from a point of the experimentalism: TLOT faces considerable counter-examples such as cases, 'observation precedes theory' and 'the combination of wrong theory and right observation'. I introduce a distinction between the guiding theory and the target theory in experimental situations and illustrate that TLOT loses its alleged power if we consider the distinction. Lastly, I suggest NEA, as conclusion of the paper, which can mediate among TIOT, TLOT, and experimentalism and takes a minimal ontology.

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Development and Validation of a Clinical Critical Thinking Skills Scale (임상적 비판적 사고능력 검사도구 개발 및 평가)

  • Shin, Su-Jin;Yang, Eunbae;Kong, Byunghea;Jung, Dukyoo
    • Korean Medical Education Review
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    • v.14 no.2
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    • pp.102-108
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    • 2012
  • This study developed a test entitled Clinical Critical Thinking Skills (CCTS) by using item response theory (IRT) and examined its validity. In the development stage, data obtained from a convenience sample of 627 undergraduate nursing students were analyzed using a discrimination and difficulty index with the TestAn 1.0 program. In the evaluation stage, data from a convenience sample of 284 nursing and non-nursing students were analyzed using a discrimination and difficulty index with the BILOG-MG program. Criterion validity was verified by the group comparison method. Five items received low discrimination index scores according to the IRT results. In terms of the criterion validity, CCTS scores differed according to major (t=2.21, p=0.028), location of high school (F=4.35, p=0.014), clinical experience (t=5.66, p=0.004), and grade point average (F=7.17, p< 0.001). The CCTS can be used to measure critical thinking skills in the clinical setting.

Experience of Clinical Adaptation among Nurses in Intensive Care Unit (중환자실 간호사의 임상 적응 경험)

  • Hong, Jin Young;Sohn, Sue Kyung
    • Journal of Korean Critical Care Nursing
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    • v.17 no.1
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    • pp.1-16
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    • 2024
  • Purpose : This study aimed to explore and describe intensive care unit (ICU) nurses' experience of clinical adaptation. Methods : The participants were 14 ICU nurses with more than two years of working experience in the ICU. Data were collected through in-depth individual interviews conducted between July and October 2021. Theoretical sampling was used to the point of theoretical saturation. Data were analyzed using the Strauss and Corbin method. Results : A total of 79 concepts, 37 subcategories, and 16 categories were identified through open coding. Axial coding based on the paradigm model revealed that the central phenomenon was "The harsh adversity faced in the nursing field where life and death are determined" and the core category was "Enduring the adversity of caring for critically ill patients and achieving self-realization." ICU nurses' clinical adaptation process was explained in five phases: "confrontation period," "turbulent period," "seeking period," "struggling period," and "stabilized period." The five phases that affect interventional conditions were "Support from reliable people," "Recognition of administrative and financial support." Conclusion : This study provided novel insights for a comprehensive understanding of ICU nurses' clinical adaptation processes. Furthermore, the findings are expected to be used as basic data to develop multifaceted strategies to help ICU nurses' adaptation to critical care.

A method of inferring collision ratio based on maneuverability of own ship under critical collision conditions

  • You, Youngjun;Rhee, Key-Pyo;Ahn, Kyoungsoo
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.5 no.2
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    • pp.188-198
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    • 2013
  • In constructing a collision avoidance system, it is important to determine the time for starting collision avoidance maneuver. Many researchers have attempted to formulate various indices by applying a range of techniques. Among these indices, collision risk obtained by combining Distance to the Closest Point of Approach (DCPA) and Time to the Closest Point of Approach (TCPA) information with fuzzy theory is mostly used. However, the collision risk has a limit, in that membership functions of DCPA and TCPA are empirically determined. In addition, the collision risk is not able to consider several critical collision conditions where the target ship fails to take appropriate actions. It is therefore necessary to design a new concept based on logical approaches. In this paper, a collision ratio is proposed, which is the expected ratio of unavoidable paths to total paths under suitably characterized operation conditions. Total paths are determined by considering categories such as action space and methodology of avoidance. The International Regulations for Preventing Collisions at Sea (1972) and collision avoidance rules (2001) are considered to solve the slower ship's dilemma. Different methods which are based on a constant speed model and simulated speed model are used to calculate the relative positions between own ship and target ship. In the simulated speed model, fuzzy control is applied to determination of command rudder angle. At various encounter situations, the time histories of the collision ratio based on the simulated speed model are compared with those based on the constant speed model.

Daesoon Thought Explained Through the Philosophy of the Book of Change (대순사상의 역학적 조명 - 종지(宗旨)를 중심으로 -)

  • Choi, Young-Jin
    • Journal of the Daesoon Academy of Sciences
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    • v.20
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    • pp.169-191
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    • 2009
  • The Four Tenets of Daesoon thought are the Creative conjunction of the virtues of Eum and Yang, the Harmonious union of divine beings and human beings, the Resolution of grievances for the mutual beneficence of all life and the Realization of the Dao in the world. This article compares the concepts of the "Creative conjunction of the virtues of Eum and Yang", the "Harmonious union of divine beings and human beings" and the "Resolution of grievances for the mutual beneficence of all life" with "EumYangDaeDaeRon", "ShinMyonKiDeok", the Theory of Mutual Giving Life / Mutual Destruction (SangSaeng/SangGeukRon) of the Book of Changes and analyzes their common and different points. The conclusion is that Daesoon thought and the philosophy of the Book of Changes share common fundamental standpoints. However, the Daesoon thought defines the world of SeonCheon (the state before the Heaven and Earth have been created) as Mutual Giving Life (SangSaeng), and the world of HuCheon (the state after the Heaven and Earth have been created) as Mutual Destruction (SangGeuk). According to Daesoon thought the Mutual Destruction (SangGeuk) is seen as negative, while according to the philosophy of the Book of Changes the Theory of Mutual Giving Live/Mutual Destruction (SangSaeng/SangGeukRon) is viewed as a positive relationship of EumYangDaeDae. This is a point of difference between the Daesoon thought and the philosophy of the Book of Changes. According to EumYangDaeDae relationship theory the contradictory "other" is viewed not as an enemy, but as a necessary element that assures one's existence. When Buddhism and Christianity first came to existence, they did not belong to a main stream. Later, through continuous theorization and systematization they became generally accepted religions. The case of Confucianism was not much different. During Song dynasty in China Buddhism has contributed to the systematization and establishment of Neo-Confucianism; in the middle of 20th century the Confucian scholars of Hong Kong and Taiwan interpreted and defined Confucianism a new in the light of Western philosophy. Thus the "Modern Neo-Confucianism" came to existence. That's why the history of Confucianism is also called "the history of advancing and developing a concept". From this point of view the critical acceptance of some elements of Confucian, Buddhist, Taoist etc. traditions, as well as modern philosophy, by Daesoon, in order to achieve the systematization of Daesoon thought, is a very important process. As a part of this process, this essay explains the Daesoon thought from the point of view of the Book of Changes, which may be said to present the original East-Asian view of the world. Daesoon's emphasis of human dignity, the equality of sexes, the critics the hierarchical society etc. are rather "modern" and should be examined from the point of view of social science. Besides, leaving the boundaries of "modern philosophy", the concepts of "Harmonious union of divine beings and human beings", viewing the universe as one organism etc. should be approached from the point of view of Post-Modernism.

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Core${\cdot}$Quality${\cdot}$Basic Service Factors of Family Restaurants and Differentiation Strategy for Customer Service Management (패밀리 레스토랑의 핵심${\cdot}$고품질${\cdot}$기본서비스 요인과 요인 별 고객관리 차별화 전략에 관한 연구)

  • Park, Jung-Young
    • Journal of the Korean Society of Food Culture
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    • v.23 no.2
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    • pp.184-193
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    • 2008
  • The purpose of this study was to determine the detailed customer satisfaction and dissatisfaction factors of family restaurants in Korea, and to then classify the factors into 3 groups, inlcuding core service, quality service, and basic service. ‘Core service’ represents the critical factors that generate both satisfaction and dissatisfaction; ‘quality service’ generates only satisfaction; and ‘basic service’ generates only dissatisfaction. This categorization is based on Herzberg’s motivation-hygiene theory (1976) as well as Cadotte & Turgeon (1988). Based on the characteristics of the three groups, differentiation strategies in managing customer service were suggested to the family restaurant managers. A qualitative research method, termed the critical incident technique (CIT), was used in the study. This method helps researchers find new factors or attributes by grouping key issues from the anecdotes (critical incidents) and then categorizing common factors from the key issues. This research categorized key satisfiers and dissatisfiers into 33 factors, which were from 402 critical incidents described by 261 respondents. Eleven factors (response to service failures, food taste and quality, attention paid to customers, coupon/mileage point/discount card, customer’s ordinary requests, waiting, food diversity, food price, facility sanitation, checking out, customer’s special requests) were classified into core service, which required maximum management not regarding the level of customer satisfaction. Six factors (employee attitude, event, education and explanation, complementary food, customer’s mistakes, attention paid to children) were classified into quality service, which required differentiation strategy management. Finally, nine factors (speed of food service, employee’s mistakes, food sanitation, atmosphere and interior, seating, forcing orders, parking, other customers, reservations) were classified into basic service, which required minimum management at the level of the industry standards.

Network Attack and Defense Game Theory Based on Bayes-Nash Equilibrium

  • Liu, Liang;Huang, Cheng;Fang, Yong;Wang, Zhenxue
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.10
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    • pp.5260-5275
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    • 2019
  • In the process of constructing the traditional offensive and defensive game theory model, these are some shortages for considering the dynamic change of security risk problem. By analysing the critical indicators of the incomplete information game theory model, incomplete information attack and defense game theory model and the mathematical engineering method for solving Bayes-Nash equilibrium, the risk-averse income function for information assets is summarized as the problem of maximising the return of the equilibrium point. To obtain the functional relationship between the optimal strategy combination of the offense and defense and the information asset security probability and risk probability. At the same time, the offensive and defensive examples are used to visually analyse and demonstrate the incomplete information game and the Harsanyi conversion method. First, the incomplete information game and the Harsanyi conversion problem is discussed through the attack and defense examples and using the game tree. Then the strategy expression of incomplete information static game and the engineering mathematics method of Bayes-Nash equilibrium are given. After that, it focuses on the offensive and defensive game problem of unsafe information network based on risk aversion. The problem of attack and defense is obtained by the issue of maximizing utility, and then the Bayes-Nash equilibrium of offense and defense game is carried out around the security risk of assets. Finally, the application model in network security penetration and defense is analyzed by designing a simulation example of attack and defense penetration. The analysis results show that the constructed income function model is feasible and practical.

A refined quasi-3D theory for stability and dynamic investigation of cross-ply laminated composite plates on Winkler-Pasternak foundation

  • Nasrine Belbachir;Fouad Bourada;Abdelmoumen Anis Bousahla;Abdelouahed Tounsi;Mohamed A. Al-Osta;Mofareh Hassan Ghazwani;Ali Alnujaie;Abdeldjebbar Tounsi
    • Structural Engineering and Mechanics
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    • v.85 no.4
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    • pp.433-443
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    • 2023
  • The current paper discusses the dynamic and stability responses of cross-ply composite laminated plates by employing a refined quasi-3D trigonometric shear deformation theory. The proposed theory takes into consideration shear deformation and thickness stretching by a trigonometric variation of in-plane and transverse displacements through the plate thickness and assures the vanished shear stresses conditions on the upper and lower surfaces of the plate. The strong point of the new formulation is that the displacements field contains only 4 unknowns, which is less than the other shear deformation theories. In addition, the present model considers the thickness extension effects (εz≠0). The presence of the Winkler-Pasternak elastic base is included in the mathematical formulation. The Hamilton's principle is utilized in order to derive the four differentials' equations of motion, which are solved via Navier's technique of simply supported structures. The accuracy of the present 3-D theory is demonstrated by comparing fundamental frequencies and critical buckling loads numerical results with those provided using other models available in the open literature.