Search results for: Yong Jung Kwon

Authors: Li-Fang CHou, Chun-Jung Tseng, Sung-Chun Tsai

Abstract:

Zhong-Yong represents unique values and cognitive beliefs of Chinese culture. Zhong-Yong thinking emphasizes (a) holistic thinking and perspective taking, (b) tolerance of contradictions, and (c) pursuance of a person’s interpersonal and inner harmony. With a unique way of naïve dialectical thinking based on Chinese culture, previous studies have found that people with higher Zhong-Yong thinking have more cognitive resources and resilience to make decision for dilemmas and cope stresses. Creativity is defined as the behavior to create novel and value products and viewed as the most important capital for individuals and enterprises. However, the relationship between Zhong-Yong thinking and creativity is still remaining to be unexplored. Three studies were conducted to explore the effects of Zhong-Yong thinking on creativity. In Study1, with 87 undergraduate students from a university in southern Taiwan as participants, we used questionnaire to measure Zhong-Yong thinking and processed creative task (unusual uses task) to get indicators of fluency and flexibility. After controlling background and openness to experience of Big five, the results showed that Zhong-Yong thinking had significant positive effects on fluency and flexibility. In Study 2, 97 undergraduate students were recruited to do Zhong-Yong thinking task and creative task. The result showed that, compared with control group, the participants had higher creative performance after being primed with Zhong-Yong thinking. In Study 3, we adopted questionnaire survey and took 397 employees from private enterprises in Taiwan as sample. Besides the main effects of Zhong-Yong thinking, the moderating effects on the relationship between leadership behavior and employee’s creative performance were also investigated. We found that (a) Zhong-Yong thinking was positively associated to creative performance; (b) Zhong-Yong thinking strengthened the positive effects of transformational and authoritative leadership on creative performance. Finally, the implications of theory/practice and limitations/future directions were also discussed.

Keywords: Zhong-Yong thinking, creativity and creative performance, unusual uses task, transformational leadership, authoritative leadership

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Authors: Eman Alhajjar, Albatool Jamjoom, Fatmah Bugshan

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This research aims to investigate the artificial intelligence (AI) application Jung GPT and how helpful it is, as a therapy AI, to users. Jung GPT has the potential to make mental health care more accessible and cheaper while also providing tailored support and advice. However, it is not intended to be a substitute for human therapists. Jung GPT is instructed to understand a wide range of concepts, including emojis, sensitive subjects, and various languages. Furthermore, participants were asked to fill out a survey based on their experience with Jung GPT. Additionally, analysis of the responses indicated that Jung GPT was helpful in identifying and exploring challenges, and the use of Jung GPT by participants in the future is highly possible. The results demonstrate that Jung GPT does help in recognizing challenges or problems within the users. On this basis, it is recommended that individuals use Jung GPT to explore their thoughts, feelings, and challenges. Moreover, further research is needed to better evaluate the effectiveness of Jung GPT.

Keywords: Jung GPT, artificial intelligence, therapy, mental health, AI application

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Authors: Jae-Yong Sim, Jung-Hun Kwon, Ji-Sung Park, Kee-Joe Lim

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One of the latest trends for insulation systems to improve the insulation performance is the use of eco-friendly hybrid insulation using compressed dry-air. Despite the excellent insulation performance of sulphurhexafluoride (SF6) gas, its use has been restricted due to the problems with significant global warming potential (GWP). Accordingly, lightning impulse performance of the hybrid insulation system covered with an aluminum trihydrate/silicone rubber (ATH/SIR) nanocomposite was examined in air at atmospheric pressure and in compressed air at pressures between 0.2 and 0.6 MPa. In the experiments, the most common breakdown path took place along the surface of the covered rod. The insulation reliability after several discharges should be guaranteed in hybrid insulation. On the other hand, the surface of the covered rod was carbonized after several discharges. Therefore, nanoscale ATH can be used as a reinforcement of covered dielectrics to inhibit carbonization on the surface of a covered rod. The results were analyzed in terms of the surface resistivity of the cover dielectrics.

Keywords: nanocomposite, hybrid insulation, ATH, dry-air

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Authors: Yong Seo Koo, Jong Ho Nam, Yong Nam Choi, Dae Yeol Yoo, Jung Woo Han

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This paper presents a silicon controller rectifier (SCR) based ESD protection circuit for IC. The proposed ESD protection circuit has low trigger voltage and high holding voltage compared with conventional SCR ESD protection circuit. Electrical characteristics of the proposed ESD protection circuit are simulated and analyzed using TCAD simulator. The proposed ESD protection circuit verified effective low voltage ESD characteristics with low trigger voltage and high holding voltage.

Keywords: electro-static discharge (ESD), silicon controlled rectifier (SCR), holding voltage, protection circuit

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Authors: Shirin Ghasemi

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The structure of Asadi’s poem in Garshasb-Nameh coordinates with the structure of human psyche based on Jung’s perspective. The poetic stories of Asadi in Garshasb-Nameh is contrasted to human psyche according to Jung’s view in psychology which indicated the similarity of poetic structure of stories of Garshasb-Nameh to analytical psychology of Jung. In fact, by studying the stories of this collection the reader travels with him and finds it consistent with the human psyche. To demonstrate this, the story of Jamshid marriage with Kuhrang’s daughter and the story of Garshasb marriage with King’s daughter are selected. These two stories illustrate the poetic structure and the human psyche based on Jung’s analytical psychology perspective.

Keywords: Asadi Tusi, Garshasb-Nameh, Jung, analytical psychology

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Authors: Md. Ruhul Amin, Shakura Namni, Md. Ramiz Uddin Miah, Md. Giashuddin Miah, Mohammad Zakaria, Sang Jae Suh, Yong Jung Kwon

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Insect species abundance and diversity associated with meteorological factors during January to June 2013 at a mango-based agroforestry research field in Bangladesh, and the effects of pests and pollinator species on mango are presented in this study. Among the collected and identified insects, nine species belong to 3 orders were found as pollinator, 11 species in 5 orders as pest, and 13 species in 6 orders as predator. The mango hopper, fruit fly and stone weevil appeared as major pest because of their high levels of abundance and infestation. The hoppers caused 100% inflorescence damage followed by fruit fly (51.7% fruit) and stone weevil (31.0% mature fruit). The major pests exerted significantly higher abundance compared to pollinator, predator and minor pests. Hemipteroid insects were most abundant (60%) followed by Diptera (21%), Hymenoptera (10%), Lepidoptera (5%), and Coleoptera (4%). Insect population increased with increasing trend of temperature and humidity, and revealed peak abundance during April-May. The flower visiting insects differed in their landing duration and showed preference to forage with time of a day. Their foraging activity was found to be peaked between 11.00 am to 01.00 pm. The activity of the pollinators led to higher level of fruit set. This study provides baseline information about the phenological patterns of insect abundance in an agroforestry research field which could be an indication to incorporate some aspects of pest management.

Keywords: agroforestry, abundance, abiotic factors, insects, mango

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Authors: Viriyavudh Sim, Jung Kyu Choi, Yong Ju Kwak, Oh Hyeon Jeon, Woo Young Jung

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In this study, we investigated the buckling performance of basalt fiber reinforced polymer (BFRP) sandwich infill panels. Fiber Reinforced Polymer (FRP) is a major evolution for energy dissipation when used as infill material of frame structure, a basic Polymer Matrix Composite (PMC) infill wall system consists of two FRP laminates surrounding an infill of foam core. Furthermore, this type of component is for retrofitting and strengthening frame structure to withstand the seismic disaster. In-plane compression was considered in the numerical analysis with ABAQUS platform to determine the buckling failure load of BFRP infill panel system. The present result shows that the sandwich BFRP infill panel system has higher resistance to buckling failure than those of glass fiber reinforced polymer (GFRP) infill panel system, i.e. 16% increase in buckling resistance capacity.

Keywords: Basalt Fiber Reinforced Polymer (BFRP), buckling performance, FEM analysis, sandwich infill panel

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Authors: Min-ju Kwon, Chae-won Kim, Jeong-yun Seo, Hee-guk Chae, Yong-seo Koo

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In this paper, we presented the LDO (low-dropout) regulator which enhanced the PSRR by applying the constant current source generation technique through the BGR (Band Gap Reference) to form the noise sensing circuit. The current source through the BGR has a constant current value even if the applied voltage varies. Then, the noise sensing circuit, which is composed of the current source through the BGR, operated between the error amplifier and the pass transistor gate of the LDO regulator. As a result, the LDO regulator has a PSRR of -68.2 dB at 1k Hz, -45.85 dB at 1 MHz and -45 dB at 10 MHz. the other performance of the proposed LDO was maintained at the same level of the conventional LDO regulator.

Keywords: LDO regulator, noise sensing circuit, current reference, pass transistor

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Authors: Su-Hyun Jung, Young-Su Ryu, Yong-Jun Kim, Hyoung-Kyu Song

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In this paper, a highly efficient coordinated multiple-point (CoMP) scheme for vehicular communication is proposed. The proposed scheme controls the transmit power and applies proper transmission scheme for the various situations. The proposed CoMP scheme provides comparable performance to the conventional dynamic cell selection (DCS) scheme. Moreover, this scheme provides improved power efficiency compared with the conventional joint transmission (JT) scheme. Simulation results show that the proposed scheme can achieve more enhanced performance with the high power efficiency and improve the cell capacity.

Keywords: CoMP, LTE-A, V2I, V2V, V2X.

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Authors: Myung-Gon Yoon, Jung-Ho Moon, Tae Kwon Ha

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This paper deals with a stabilization problem for multi-agent systems, when all agents in a multi-agent system receive the same broadcasting control signal and the controller can measure not each agent output but the sum of all agent outputs. It is analytically shown that when the sum of all agent outputs is bounded with a certain broadcasting controller for a given reference, each agent output is separately bounded:stabilization of the sum of agent outputs always results in the stability of every agent output. A numerical example is presented to illustrate our theoretic findings in this paper.

Keywords: broadcasting control, multi-agent system, transfer function, stabilization

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Authors: Haotian Wu

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This article examines the figure Zhao Tao in Jia Zhangke’s films in light of Carl Jung’s psychoanalytical theory. Zhao is a recurring aesthetic trope in Jia’s films, and the characters she plays often have an intimate relationship with the past. Nevertheless, this relationship has not been systematically investigated, especially its symbolism of the typical relationship between the past and the self in post-social China. To fill this research gap, the article will explore how Zhao’s characters discover, preserve, and adapt the past in I Wish I knew (2010), Mountains May Depart (2015), and Ash Is Purest White (2018). Through a Jungian lens, these three levels of engagement with the past will be demonstrated as corresponding with Jung’s psychoanalytical theory of self-realisation, which entails the confrontation with the shadow, the embodiment of the archetype, and individuation. Thus, by articulating a film-philosophy dialogue between Jia and Jung, this article will develop a new philosophy of self-realisation based on the symbolism of Zhao. Through the reintegration of the past, the individuals can overcome the fragmentation of temporality and selfhood in the postmodern world and achieve self-realisation.

Keywords: Jia Zhangke, Jung, psychoanalysis, self-realisation

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Authors: Myung-Gon Yoon, Jung-Ho Moon, Tae Kwon Ha

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This paper considers a robust stabilization problem of a single agent in a multi-agent consensus system composed of identical agents, when the network topology of the system is completely unknown. It is shown that the transfer function of an agent in a consensus system can be described as a multiplicative perturbation of the isolated agent transfer function in frequency domain. Applying known robust stabilization results, we present sufficient conditions for a robust stabilization of an agent against unknown network topology.

Keywords: single agent control, multi-agent system, transfer function, graph angle

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Authors: Jung-Ho Moon, Tae Kwon Ha

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In the present study, the effect of Si, Al, Ti, Zr, and Nb addition on the microstructure and hot workability of cast M42 tool steels, basically consisting of 1.0C, 0.2Mn, 3.8Cr, 1.5W, 8.5Co, 9.2Mo, and 1.0V in weight percent has been investigated. Tool steels containing Si of 0.25 and 0.5 wt.%, Al of 0.06 and 0.12 wt.%, Ti of 0.3 wt.%, Zr of 0.3 wt.%, and Nb of 0.3 wt.% were cast into ingots of 140 mm´ 140 mm´ 330 mm by vacuum induction melting. After solution treatment at 1150°C for 1.5 hrs. followed by furnace cooling, hot rolling at 1180 °C was conducted on the ingots. Addition of titanium, zirconium and niobium was found to retard the decomposition of the eutectic carbides and result in the deterioration of hot workability of the tool steels, while addition of aluminium and silicon showed relatively well decomposed carbide structure and resulted in sound hot rolled plates.

Keywords: high speed steels, alloying elements, eutectic carbides, microstructure, hot workability

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Authors: Laurence Doremus

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Freud as the builder of psychoanalysis as a discipline had created the science with Carl Gustav Jung (1875-1961), a psychiatry specialist from Zurich who was very important in the Freudian theory. The knowledge about the foundation of psychoanalysis is often focused on the influence of the works from Breuer or Charcot in the Freudian praxis, at least at the beginning of his career, and Jung's influence is often under-estimated. The paper focuses on the importance of the Jungian contributions in Freud's theories at the beginning of the creation of the discipline in the 1910s. We often meet Jungian schools on the first hand and Freudian schools, on the other hand in the academic field, but the Freudian field has to admit the importance of the Jungian theories in Freudian science. And also, the dialectical energy which appears in the letters exchanged between both of the fathers of psychoanalysis is important to understand the foundations of Freud Theory. That's why the paper will analyze in detail the correspondence between them in an epistemological and historical approach. Effectively the letters were translated and published (in French but also in English and other languages) lately in history and are still not well knew by the researchers in the psychoanalytical field. We well explain how Freud was helped by Jung despite his desire to build the theory. We analyze how the second topic named 'unconscious, preconscious, and conscious', is the result of the first topic that Jung built with Freud. The paper is a contribution to the knowledge we should have about the intense friendship between the two protagonists.

Keywords: Carl Gustav Jung, correspondence, Freud's letters, psychoanalytic theory

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Authors: Tae-Hoon Kim, Kwon-Ha Yoon, Hong Young Jun, Ki-Jong Kim, Young Hwan Lee, Myeung Su Lee, Keum Ha Choi, Ki Jung Yun, Eun Young Cho, Yong-Yeon Jeong, Chung-Hwan Jun

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Purpose: To assess the changes of hepatic metabolite for differentiation between non-alcoholic steatohepatitis (NASH) and simple steatosis on proton magnetic resonance spectroscopy (1H-MRS) in both humans and animal model. Methods: The local institutional review board approved this study and subjects gave written informed consent. 1H-MRS measurements were performed on a localized voxel of the liver using a point-resolved spectroscopy (PRESS) sequence and hepatic metabolites of alanine (Ala), lactate/triglyceride (Lac/TG), and TG were analyzed in NASH, simple steatosis and control groups. The group difference was tested with the ANOVA and Tukey’s post-hoc tests, and diagnostic accuracy was tested by calculating the area under the receiver operating characteristics (ROC) curve. The associations between metabolic concentration and pathologic grades or non-alcoholic fatty liver disease(NAFLD) activity scores were assessed by the Pearson’s correlation. Results: Patient with NASH showed the elevated Ala(p<0.001), Lac/TG(p < 0.001), TG(p < 0.05) concentration when compared with patients who had simple steatosis and healthy controls. The NASH patients were higher levels in Ala(mean±SEM, 52.5±8.3 vs 2.0±0.9; p < 0.001), Lac/TG(824.0±168.2 vs 394.1±89.8; p < 0.05) than simple steatosis. The area under the ROC curve to distinguish NASH from simple steatosis was 1.00 (95% confidence interval; 1.00, 1.00) with Ala and 0.782 (95% confidence interval; 0.61, 0.96) with Lac/TG. The Ala and Lac/TG levels were well correlated with steatosis grade, lobular inflammation, and NAFLD activity scores. The metabolic changes in human were reproducible to a mice model induced by streptozotocin injection and a high-fat diet. Conclusion: 1H-MRS would be useful for differentiation of patients with NASH and simple hepatic steatosis.

Keywords: non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, 1H MR spectroscopy, hepatic metabolites

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Authors: Jung-Ho Moon, Tae Kwon Ha

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The effect of Yttrium addition on the microstructure and mechanical properties of Sn-Zn eutectic alloy, which has been attracting intensive focus as a Pb-free solder material, was investigated in this study. Phase equilibrium has been calculated by using FactSage® to evaluate the composition and fraction of equilibrium intermetallic compounds and construct a phase diagram. In the case of Sn-8.8 Zn eutectic alloy, the as-cast microstructure was typical lamellar. With addition of 0.25 wt. %Y, a large amount of pro-eutectic phases have been observed and various YZnx intermetallic compounds were expected to successively form during cooling. Hardness of Sn-8.8 Zn alloy was not affected by Y-addition and both alloys could be rolled by 90% at room temperature.

Keywords: Sn-Zn eutectic alloy, yttrium, FactSage®, microstructure, mechanical properties

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Authors: Jun-Geol Park, Kyoung-Il Do, Min-Ju Kwon, Kyung-Hyun Park, Yong-Seo Koo

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In this paper, we proposed the SCR (Silicon Controlled Rectifier)-based ESD (Electrostatic Discharge) protection circuit for latch-up immunity. The proposed circuit has a lower trigger voltage and a higher holding voltage characteristic by using the zener diode structure. These characteristics prevent latch-up problem in normal operating conditions. The proposed circuit was analyzed to figure out the electrical characteristics by the variations of design parameters D1, D2 and stack technology to obtain the n-fold electrical characteristics. The simulations are accomplished by using the Synopsys TCAD simulator. When using the stack technology, 2-stack has the holding voltage of 6.9V and 3-stack has the holding voltage of 10.9V.

Keywords: ESD, SCR, trigger voltage, holding voltage

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Authors: Yong-Nam Kwon

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In the present study, we have designed the hydro-mechanical forming in which AZ31 sheet was drawn to a kind of preform step following gas blow forming for accurate geometry. In order to judge a formability enhancement of AZ31 sheet, model geometry came from a practical automotive part which had quite depth with complicated curvatures, which was proven that a single sheet forming could not gave a successful part. Experimentally, we succeeded to make the model part with accurate dimension. The optimum forming conditions for respective forming steps were considered most important technical features of this hydro-mechanical and would be discussed in details. Also, the effort to avoid detrimental abnormal grain growth was given and discussed for a practical application.

Keywords: hydro-mechanical forming, AZ31, abnormal grain growth, model geometry

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Authors: Sung-yong Choi, Woo-tai Jung, Young-hwan Park

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This study intends to improve the bond performance of the polypropylene fiber used as reinforcing fiber for concrete by changing its shape into double crimped type through the enhancement its fabrication process. The bond performance of such double crimped fiber is evaluated by applying the JCI SF-8 (dog-bone shape) testing method. The test results reveal that the double crimped fiber develops bond performance improved by more than 19% compared to the conventional crimped type fiber.

Keywords: Bond, Polypropylene, fiber reinforcement, macro fiber, shape change

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Authors: Min Ho Kwon, Woo Young Jung, Hyun Su Seo

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A Polymer Cement Mortar (PCM) has been widely used as the material of repair and restoration work for concrete structure; however a PCM usually induces an environmental pollutant. Therefore, there is a need to develop PCM which is less impact to environments. Usually, UM resin is known to be harmless to the environment. Accordingly, in this paper, the properties of the PCM using UM resin were studied. The general cement mortar and UM resin was mixed in the specified ratio. A certain percentage of PVA fibers, steel fibers and mixed fibers (PVA fiber and steel fiber) were added to enhance the flexural strength. The flexural tests were performed in order to investigate the flexural strength of each PCM. Experimental results showed that the strength of proposed PCM using UM resin is improved when they are compared with general cement mortar.

Keywords: polymer cement mortar, UM resin, compressive strength, PVA fiber, steel fiber

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Authors: Jung-Ho Moon, Tae Kwon Ha

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Abstract—High temperature deformation behavior of cast Fe-20Cr-5Al alloy has been investigated in this study by performing tensile and compression tests at temperatures from 1100 to 1200oC. Rectangular ingots of which the dimensions were 300×300×100 in millimeter were cast using vacuum induction melting. Phase equilibrium was calculated using the FactSage®, thermodynamic software and database. Tensile strength of cast Fe-20Cr-5Al alloy was 4 MPa at 1200oC. With temperature decreased, tensile strength increased rapidly and reached up to 13 MPa at 1100oC. Elongation also increased from 18 to 80% with temperature decreased from 1200oC to 1100oC. Microstructure observation revealed that M23C6 carbide was precipitated along the grain boundary and within the matrix.

Keywords: 20 Cr-5Al ferritic stainless, high temperature deformation, aging treatment, microstructure, mechanical properties

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Authors: Jung Ho Yang, Yong Soo Kim

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Electrical units are operated by electrical and electronic components. An environmental test sequence is useful for testing electrical units to reduce reliability issues. This study introduces test sequence guidelines based on relevant principles and considerations for electronic testing according to international standard IEC-60068-1 and the United States military standard MIL-STD-810G. Then, test sequences were proposed based on the descriptions for each test. Finally, General Motors (GM) specification GMW3172 was interpreted and compared to IEC-60068-1 and MIL-STD-810G.

Keywords: reliability, environmental test sequence, electrical units, IEC 60068-1, MIL-STD-810G

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Authors: Hyun-Jee Yang, Bit-Na Kwon, Yong-Jun Kim, Hyoung-Kyu Song

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In the cooperative transmission scheme, both the cellular system and broadcasting system are composed. Two cellular base stations (CBSs) communicating with a user in the cell edge use cooperative transmission scheme in the conventional scheme. In the case that the distance between two CBSs and the user is distant, the conventional scheme does not guarantee the quality of the communication because the channel condition is bad. Therefore, if the distance between CBSs and a user is distant, the performance of the conventional scheme is decreased. Also, the bad channel condition has bad effects on the performance. The proposed scheme uses two relays to communicate well with CBSs when the channel condition between CBSs and the user is poor. Using the relay in the high attenuation environment can obtain both advantages of the high bit error rate (BER) and throughput performance.

Keywords: cooperative communications, diversity gain, OFDM, interworking system

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Authors: Myoung-Gon Yoon, Jung-Ho Moon, Tae Kwon Ha

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Tensile specimens of nonflammable AZ91D Mg alloy were fabricated in this study via cold chamber die-casting process. Dimensions of tensile specimens were 25mm in length, 4mm in width, and 0.8 or 3.0mm in thickness. Microstructure observation was conducted before and after tensile tests at room temperature. In the die casting process, various injection distances from 150 to 260mm were employed to obtain optimum process conditions. Distribution of Al12Mg17 phase was the key factor to determine the mechanical properties of die-cast Mg alloy. Specimens with 3mm of thickness showed superior mechanical properties to those with 0.8mm of thickness. Closed networking of Al12Mg17 phase along grain boundary was found to be detrimental to mechanical properties of die-cast Mg alloy.

Keywords: non-flammable magnesium alloy, AZ91D, die-casting, microstructure, mechanical properties

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Authors: Yong-Su Jo, Seung-Min Yang, Seok Hong Min, Tae Kwon Ha

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The synthesis of nickel nanoparticles by the reduction of nickel chloride with hydrazine in an aqueous solution. The effect of hydrazine concentration on batch-processed particle characteristics was investigated using Field Emission Scanning Electron Microscopy (FESEM). Both average particle size and geometric standard deviation (GSD) were decreasing with increasing hydrazine concentration. The continuous synthesis of nickel nanoparticles by microemulsion method was also studied using FESEM and X-ray Diffraction (XRD). The average size and geometric standard deviation of continuous-processed particles were 87.4 nm and 1.16, respectively. X-ray diffraction revealed continuous-processed particles were pure nickel crystalline with a face-centered cubic (fcc) structure.

Keywords: nanoparticle, hydrazine reduction, continuous process, microemulsion method

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Authors: Kwon Eunhee, Park Dongcheon, Jung Jaemin

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In countries around the world, environmental regulations are being strengthened, and Korea is no exception to this trend, which means that environment pollution and the environmental load have recently become a significant issue. For this reason, in this study limestone was replaced with cementitious powder to reduce the volume of construction waste as well as the emission of carbon dioxide caused by Tal-carbonate reaction. The research found that cementitious powder can be used as a substitute for limestone. However, the mix proportions of fine aggregate and powder included in the cementitious powder appear to have a great effect on substitution. Thus, future research should focus on developing a technology that can effectively separate and discharge fine aggregate and powder in the cementitious powder.

Keywords: waste cementitious powder, fine aggregate powder, CO2 emission, decarbonation reaction, calcining process

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Authors: Jung-Ho Moon, Myung-Gon Yoon, Tae Kwon Ha

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This paper presents a wireless sensor network protocol for a car parking monitoring system. A wireless sensor network for the purpose is composed of multiple sensor nodes, a sink node, a gateway, and a server. Each of the sensor nodes is equipped with a 3-axis AMR sensor and deployed in the center of a parking space. The sensor node reads its sensor values periodically and transmits the data to the sink node if the current and immediate past sensor values show a difference exceeding a threshold value. The operations of the sink and sensor nodes are described in detail along with flow diagrams. The protocol allows a low-duty cycle operation of the sensor nodes and a flexible adjustment of the threshold value used by the sensor nodes.

Keywords: car parking monitoring, sensor node, wireless sensor network, network protocol

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Authors: Seung-Jun Yu, Yong-Jun Kim, Jung-In Baik, Hyoung-Kyu Song

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In this paper, a dual-hop relay based on channel state is studied. In the conventional relay scheme, a relay uses the same modulation method without reference to channel state. But, a relay uses an adaptive modulation method with reference to channel state. If the channel state is poor, a relay eliminates latter 2 bits and uses Quadrature Phase Shift Keying (QPSK) modulation. If channel state is good, a relay modulates the received symbols with 16-QAM symbols by using 4 bits. The performance of the proposed scheme for Symbol Error Rate (SER) and throughput is analyzed.

Keywords: adaptive transmission, channel state, dual-hop, hierarchical modulation, relay

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Authors: Jung-Ho Moon, Tae Kwon Ha

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Continually increasing working temperature and growing need for greater efficiency and reliability of automotive exhaust require systematic investigation into the thermal fatigue properties especially of high temperature stainless steels. In this study, thermal fatigue properties of 300 series austenitic stainless steels have been evaluated in the temperature ranges of 200-800°C and 200-900°C. Systematic methods for control of temperatures within the predetermined range and measurement of load applied to specimens as a function of temperature during thermal cycles have been established. Thermal fatigue tests were conducted under fully constrained condition, where both ends of specimens were completely fixed. Load relaxation behavior at the temperatures of thermal cycle was closely related with the thermal fatigue property.

Keywords: austenitic stainless steel, automotive exhaust, thermal fatigue, microstructure, load relaxation

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Authors: Woo-Young Jung, Minho Kwon

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Seismic design criteria based on performance of structures have recently been adopted by practicing engineers in response to destructive earthquakes. A simple but efficient structural-analysis tool capable of predicting both the strength and ductility is needed to analyze reinforced concrete (RC) structures under such event. A three-dimensional lattice model is developed in this study to analyze torsions in high-strength RC members. Optimization techniques for determining optimal variables in each lattice model are introduced. Pure torsion tests of RC members are performed to validate the proposed model. Correlation studies between the numerical and experimental results confirm that the proposed model is well capable of representing salient features of the experimental results.

Keywords: torsion, non-linear analysis, three-dimensional lattice, high-strength concrete

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