• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.11
• /
• pp.935-942
• /
• 2014

A numerical analysis of the effect of the Prandtl number on the natural convection in a cold outer tilted square enclosure with an inner hot circular cylinder is presented. Several Prandtl numbers (Pr=0.1, 0.7, 7) are considered, with different angles($0^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$) for the enclosure and Rayleigh numbers ($Ra=10^3$, $10^4$, $10^5$). The effect of the Prandtl number on the natural convection is analyzed using isotherms and streamline and surface-averaged Nusselt numbers. The flow and heat transfer characteristics are found to be dependent on the time for $Ra=10^5$ and Pr=0.1 at angles of $0^{\circ}$ and $45^{\circ}$. However, in the other cases, the flow and heat transfer characteristics are independent of the time.The surfaceaveraged Nusselt number increases with an increase in the Prandtl number. As the Prandtl number increases, the Nusselt number becomes larger regardless of the angle for $Ra=10^5$. In particular, the Nusselt number steeply increases when the angle is $45^{\circ}$ for $Ra=10^5$ and Pr=0.1.

• Horticultural Science & Technology
• /
• v.28 no.3
• /
• pp.434-441
• /
• 2010

'Wonhwang' pear ($Pyrus$ $pyrifolia$ Nakai) often showed physiological disorder and quality deterioration during long-term storage and shelf life although this cultivar has the advantage of a good appearance and better taste for overseas exportation. This study was conducted to investigate the effect of temperature during transportation and continuing market temperature on fruit quality, and the occurrence of physiological disorder to set up the appropriate transportation and distribution temperatures in the fruits harvested at different times. Unripe fruits harvested 120 days after full bloom maintained higher firmness until 21days of shelf life at both 18 and $25^{\circ}C$ than late harvested ones. Otherwise, ripe fruits harvested 130 days after full bloom showed high incidence of mealiness breakdown of flesh tissues in 21 days of shelf-life at $25^{\circ}C$ of market temperature, but not in the fruits stored at $18^{\circ}C$. Late harvested fruits showed much severe physiological disorders when compared with early harvested ones that showed relatively lower respiration rates. Fruit quality parameters were more highly affected by market temperature than transportation temperature. Results showed that unripe fruits harvested at 120 days after full bloom maintains high marketability until 21 days of shelf-life, while the maximum shelf-life of ripe fruits harvested 130 days after full bloom will be considered at within 7 days.

• Gut and Liver
• /
• v.12 no.6
• /
• pp.682-693
• /
• 2018

Background/Aims: Intestinal barrier dysfunction is a hallmark of inflammatory bowel diseases (IBDs) such as ulcerative colitis. This dysfunction is caused by increased permeability and the loss of tight junctions in intestinal epithelial cells. The aim of this study was to investigate whether estradiol treatment reduces colonic permeability, tight junction disruption, and inflammation in an azoxymethane (AOM)/dextran sodium sulfate (DSS) colon cancer mouse model. Methods: The effects of $17{\beta}$-estradiol (E2) were evaluated in ICR male mice 4 weeks after AOM/DSS treatment. Histological damage was scored by hematoxylin and eosin staining and the levels of the colonic mucosal cytokine myeloperoxidase (MPO) were assessed by enzyme-linked immunosorbent assay (ELISA). To evaluate the effects of E2 on intestinal permeability, tight junctions, and inflammation, we performed quantitative real-time polymerase chain reaction and Western blot analysis. Furthermore, the expression levels of mucin 2 (MUC2) and mucin 4 (MUC4) were measured as target genes for intestinal permeability, whereas zonula occludens 1 (ZO-1), occludin (OCLN), and claudin 4 (CLDN4) served as target genes for the tight junctions. Results: The colitis-mediated induced damage score and MPO activity were reduced by E2 treatment (p<0.05). In addition, the mRNA expression levels of intestinal barrier-related molecules (i.e., MUC2, ZO-1, OCLN, and CLDN4) were decreased by AOM/DSS-treatment; furthermore, this inhibition was rescued by E2 supplementation. The mRNA and protein expression of inflammation-related genes (i.e., KLF4, NF-${\kappa}B$, iNOS, and COX-2) was increased by AOM/DSS-treatment and ameliorated by E2. Conclusions: E2 acts through the estrogen receptor ${\beta}$ signaling pathway to elicit anti-inflammatory effects on intestinal barrier by inducing the expression of MUC2 and tight junction molecules and inhibiting pro-inflammatory cytokines.

• Cross-Cultural Studies
• /
• v.26
• /
• pp.123-144
• /
• 2012

In the modern society in which globalization and localization proceed simultaneously, diversified and rapid migration of diaspora makes a new from of boundary off the frame of the state and the nation. This new border accompanies cultural change and racial mixture; retains ethnic conflict, the gap between rich and poor, alienation and discrimination, as well as power conflict; and extends its influence. Nowadays, the countries all over the world including Korea face problem of Diaspora in numerous forms. And each country takes an approach to the problem of the diaspora in the aspects of their society, culture and political technology. This implies that most countries, without understanding the new form of border which is alive and dynamic, define and conceptualize the diaspora in the frame of one state and one nation to carry forward the policies accordingly, resulting in inequal, incomplete and awkward homogenization. This study aimed to explore the identity of the diaspora, the core for the problem solving. Of course, studies about the identity of the diaspora have been continued until today and many great outcomes have been achieved. Nevertheless, this study aimed to explore the identity of the diaspora and the national policies which have a close interrelationship with it. It is because the study ultimately aimed to highlight the interrelationship between the destination countries, Russia and China, and the diaspora, through the definition and the classification of Russian diaspora and Chinese diaspora and the analysis of the national policies about that. However, the intention was not to distinguish superiority through the comparison of the polices about the diaspora between two countries, but to focus on the diversity of the identity of the diaspora through defining each different diaspora and paralleling the policies. Second, the reason for looking into the diaspora policies of these two countries is because it is judged the changes in the diaspora policies of each country is one of the active factors for the changes in the identify of the diaspora of each country and it is the basic research for the study on the identity of the diaspora. New migration of diaspora changes the identity of the state, and the state makes the policies and enforce the policies, resulting in the influence on the diaspora. This interaction acts as the growth factor for the new boundary. The causes of Russian diaspora and Chinese diaspora show apparent 'differences'. In parallel with this, the policies about the diaspora in Russia and China arouse 'differences' to the diaspora. The variation of the identity of the diaspora made by these differences will suggest other viewpoints on the diaspora, and these viewpoints will become the foundation for solving the problem of the diaspora in the present times.

• Cross-Cultural Studies
• /
• v.34
• /
• pp.93-114
• /
• 2014

Gaston Bachelard had a revolutionary progress in the field of human understanding by proposing his theory of image and imagination. His theory of the new image was so powerful, almost all areas of human science, particularly that of literary criticism, were strongly influenced and this influence continues until today. Today almost everyone accepts his theory of the image without much objection, but not rarely asked where began his transfer from the philosophy of science to the images. We propose a hypothesis that the beginning of the new concept of Bachelard's image was inspired by studies of contemporary science, especially quantum mechanics. The Heisenberg's uncertainty principle was the core of quantum mechanics, and opens new perspectives on the material world. We could summarize the message of the uncertainty principle : the material world is made up of various layers, and the material can not be measured by the location and movement at the same time. So we must have a new point of view of another dimension to know this material world. Bachelard had accepted this view of Heisenberg and developed his own theory of epistemological rupture. What is revolutionary in the theory of Bachelard's image is the fact that he looked at the images with the new perspective. The human psyche is another world compared to the rational world that dominates our daily lives. Bachelard insists that the image can not be explained by the concept. The fantasy world is a totally different world to that of rationality. That is why it can not be explained by the language of rationality as the concept. The imaginary world exists independently of the real world, but it is superimposed on the real world. These two worlds are influencing each other, and it is between these two world where our daily lives continues. The declaration of Bachelard 'image is a specific reality' is never a metaphor or rhetorical expression. This is an ontological expression that must truthfully. The imaginary world is a world built on the image and it works according to its own law. It is not a representation or copy of the real world. But the world of imagination are not alone. It exists in the same time and space with the world of science. It is superimposed with the world of science. Both two world influence each other. Bachelard has made a revolutionary change by studying the images. He gave them their own place. It has changed the views on the images that were treated as mere representations of reality. Thanks to him, the image can have its own value, that of a factor that creates reality. Bachelard shows how we can go deep into the source of being and the universe if we look at the pictures with the eyes of other dimensions.

• Cross-Cultural Studies
• /
• v.31
• /
• pp.119-153
• /
• 2013

There is the commonness between I-Ching of Asian scriptures and Analytic Psychology of C. G. Jung as the conjunction of opposites of yin and yang. I-Ching has the base of the Great Absolute(太極) as yin and yang. Jung's psychology has the basic structure of opposite contents of psyche. The former wants to find the proper answer for the situation as fortune book, the latter realization of personal psyche. At this basis to approach I-Ching through the Analytic Psychology can be connected with the screening its inner system and structure in the frame of depth psychology. Basically I-Ching is the scripture about the good or ill luck, regret and stinginess. All of them are related with the psychology of human beings practically. I-Ching as the main scripture of Asia has the core theme concept of the mean (中). Previously mentioned the good or ill luck, regret and stinginess are included into this as the large view point. The best decision between the given situation and the fortune teller pursues the mean(中) path of both. Jung's psychology also attaches importance to the proper balance among personal conscious, unconscious and his surrounded situations. Goodness is relied on the mean, healthy psyche the harmony with the psychological and real situations of a person. But this balance and mean cannot be achieved without any reason but by the result of the conjunction of opposites. The opposites are the Ch'ien(乾, the Creative, Heaven) and K'un(坤, the Receptive, Earth) as yin and yang in I-Ching and the conscious and unconscious in Jung's psychology. These can be opened to masculine and feminine, psyche and matter, transcendent and existence and casuality and acausal synchronicity. Conjunction of these opposites can develope and create the new conscious and creative situation. Finally yin and yang from the Great Absolute and conscious and unconscious from Self become the opposites and go through necessary step of separation and sublimation for the creation of new level. In the Great Absolute there are yin and yang and yin the latter contains the cyclic process which can make the former renew. Conjunction of opposite in Jung's psychology also go through the similar process as the Great Absolute of yin and yang.

• Korean Journal of Optics and Photonics
• /
• v.19 no.4
• /
• pp.255-261
• /
• 2008

In this study, the propagation characteristics and the fabrication tolerance of an optical wire in a flexible optical PCB were analyzed by using a ray-tracing method. It is found from the analysis that the sidewall angle of a core should be controlled within $1^{\circ}$ in order to maintain the propagation loss to less than -1 dB/mm, and that the bending radius of the optical wire should be larger than 5 mm in order to suppress the bending loss below -1 dB. In addition, it is confirmed that the lateral misalignment of ${\pm}15\;{\mu}m$, and the angular tilting of VCSEL of $6^{\circ}$ are allowable for the coupling loss of -1 dB.

• Journal of Digital Convergence
• /
• v.19 no.9
• /
• pp.169-180
• /
• 2021

This study analyzed research trends on smart logistics in Korea by conducting social network analysis (SNA) using R. The purpose of this study is to enhance the understanding of the smart logistics field along with the smart logistics status and policy review, and to suggest implications and future research tasks. The analysis period and subjects were 128 academic journal papers on smart logistics-related topics over the past 10 years (2011-2020), and the results were divided into the first half (2011-2015) and the second half (2016-2020). The analysis of the study was carried out step-by-step through frequency analysis, network centrality analysis, and visualization. As a result of the study, the quantitative increase and diversification of the research field were confirmed. It was also confirmed that the concentration of research on core areas increased by increasing the proportion of duplicate keywords. In addition, keywords with high betweenness centrality and degree centrality score such as Logistics, Authentication, Smart, Service, RFID, Technology, and Revolution were presented. Lastly, this study reviewed the structure with a focus on betweenness centrality after visualizing the network with main keywords. As a result, early research was focused on the field of logistics, and after 2016, it was confirmed that the center of research was diversifying and expanding with the development of the 4^th industrial revolution and major technologies.

• Journal of Korean Medicine Rehabilitation
• /
• v.31 no.4
• /
• pp.129-143
• /
• 2021

Objectives This study was aimed to evaluate clinical practice guidelines (CPGs) of traffic injuries, which has already been developed at domestic or outside of country, and to explore the Korean medical treatments included in the CPGs. Methods Twelve electronic databases (PubMed, Cochrane library, China National Knowledge Infrastructure [CNKI {Chinese Academic Journals, CAJ}], Research Information Sharing Service [RISS], Oriental Medicine Advanced Searching Integrated System [OASIS], KoreaMed, Korean Medical Guideline Information [KoMGI), National Guideline Clearinghouse [AHRQ], Core Outcome Measures in Effectiveness Trials Initiative Website [COMET], Turning Research into Practice [TRIP], The National Institute for Health and Care Excellence [NICE], and Medical Research Information Center [MedRIC]) up to July 2021 were searched. Only systematically developed CPGs for traffic injuries were selected and appraised. The appraisal was conducted by using Appraisal of Guidelines for Research & Evaluation (AGREE) II tool. Results Six CPGs were included and evaluated. All CPGs were appraised as highly recommended because they exceeded 60% in more than 4 among 6 domains of AGREE II, including domain of 'rigor of development', and 30% in the rest. Recommendations related to Korean medicine treatments such as on manual therapy related to Chuna were given in 6 CPGs, 4 for acupuncture, 1 for Qigong and 1 for Taping. Conclusions The 6 CPGs were developed up to now through a systematic development methodology and there were many recommendations for Korean medical treatments related to manual (Chuna) treatment, acupuncture and Qigong. However, the evidence for the side effects and risk factors of Korean medical treatments was scantly reflected in CPGs. Therefore, it is considered that balanced CPG with benefits and risks should be developed, covering Korean medical diagnosis, treatment and prognosis.

• Knowledge Management Research
• /
• v.22 no.3
• /
• pp.235-252
• /
• 2021

The development of information and communication technology and COVID-19 have caused an unusual change in the hotel industry, and the demand for the contactless services such as service robots from hotel customers has surged. Therefore, this study investigates the perception of hotel customers on contactless services by applying a mixed-method analysis. Specifically, this study identified the causal correlations between variables through the structural equation model, and further applied the fuzzy set qualitative comparison analysis to derive patterns of variables that form the intention to use the non-face-to-face services. As a result of the analysis, it was shown that service experience co-creation, palyfulness, personalization, and trust had a significant effect on intention to use through the contactless service use desire. On the other hand, in the results of fuzzy-set qualitative comparison analysis, playfulness was derived as a core factor in all patterns. Based on these analysis results, this study provides academic basis for in-depth understanding of hotel customers' perception of contactless service and specific guidelines for hotel managers on the contactless service strategies in the era of COVID-19 pandemic.