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Field Experimental Study on a Soft Protecting Method for Coastal Erosion Prevention (유연재를 이용한 연안잠식방지에 대한 현장실험 연구)

  • Peng, Ta-Hsiung;Jan, Chyan-Deng
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.13 no.3
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    • pp.216-222
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    • 2010
  • The structural methods used to protect coastal erosion are usually very expensive in construction as well as in spending on maintaining the structures from damage. Those structures like embankments, breakwaters, jetties etc. are commonly constructed with concretes (rigid methods) to protect coastal erosion. But those rigid methods are not effective always, because the wave energy and impact force on the structures could not be effectively reduced by those methods. For avoiding sediment erosion on coastal areas by the way of reducing wave energy, a flexible breakwater is introduced which will reduce energy and protect coastline economically and environmentally. The flexible device is a combination of flexible wire nets and stack of rings made of used vehicle tires and soft blades on surfaces. This flexible wire net is placed in between two stacks of rings. The stack of rings is mainly used to hold the flexible wire nets and the flexible wire net is mainly used to reduce wave energy and helps to deposit sediments in coastal area. For a field experiment study, the above-mentioned flexible breakwater of coastal protection has been set up at the Shuang-Chun coastal area in Tainan County since June 10, 2009. The length of the flexible device is 50.0 meters and the height is 2.0 meters. The function of the device has been examined by Typhoon Linfa during June 19~22, 2009 and by Typhoon Morakot during August 6~10, 2009. The result shows that the flexible breakwater has effectively trapped sediments and let them deposit on coastal. The depth of sediment deposition around the device was about 0.5 to 0.8 meters.

The Effects of Family Strength on the Ethnical Identity of Third Culture Adolescents- Focusing on the Medication Effects of Self-Esteem (제3문화 청소년의 가족건강성이 민족정체성에 미치는 영향 : 자아존중감을 매개효과로)

  • Jeon, Ji-Kyung;Rhee, Kyung-Ah;Seo, In-Doug
    • Journal of Digital Convergence
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    • v.14 no.8
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    • pp.93-104
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    • 2016
  • The purpose of this study was to examine the effects of Family Strength(FS) on the Ethnical Identity(EI) of Third Culture Adolescents and to verify the mediating effect of Self-Esteem(SE) between FS and EI. The subjects of this study were 86 adolescents from two different regions-Fairfax, Virginia and Irvine, California-who are ethnically Korean and hold either Korean or American citizenship. These analyses were carried out with SPSS 18.0, using t-test, one-way ANOVA, corelation analysis, regression analysis and Sobel test to test the significance of a mediation effect. The results of this study are as follows: 1. FS, SE and EI showed a significant positive correlation. 2. SE mediated the effects the relationship between FS and EI. 3. SE had a partial mediation effect on the relationship between FS and Exploration, a sub-variable of EI. SE also had a significant effect on Affirmation, a sub-variable of EI, but there was no significant effect on FS. The results discuss the implication and limitations of this study, and make suggestions for a follow-up study for a healthy ethnic identity formation.

Numerical Analysis of Vortex Induced Vibration of Circular Cylinder in Lock-in Regime (Lock-in 영역에서 원형실린더의 와류유기진동 전산해석)

  • Lee, Sungsu;Hwang, Kyu-Kwan;Son, Hyun-A;Jung, Dong-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.1
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    • pp.9-18
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    • 2016
  • The slender structures such as high rise building or marine riser are highly susceptible to dynamic force exerted by fluid-structure interactions among which vortex-induced vibration(VIV) is the main cause of dynamic unstability of the structural system. If VIV occurs in natural frequency regime of the structure, fatigue failure likely happens by so-called lock-in phenomenon. This study presents the numerical analysis of dynamic behavior of both structure and fluid in the lock-in regimes and investigates the subjacent phenomena to hold the resonance frequency in spite of the change of flow condition. Unsteady and laminar flow was considered for a two-dimensional circular cylinder which was assumed to move freely in 1 degree of freedom in the direction orthogonal to the uniform inflow. Fluid-structure interaction was implemented by solving both unsteady flow and dynamic motion of the structure sequentially in each time step where the fluid domain was remeshed considering the movement of the body. The results show reasonable agreements with previous studies and reveal characteristic features of the lock-in phenomena. Not only the lift force but also drag force are drastically increasing during the lock-in regime, the vertical displacement of the cylinder reaches up to 20% of the diameter of the cylinder. The correlation analysis between lift and vertical displacement clearly show the dramatic change of the phase difference from in-phase to out-of-phase when the cylinder experiences lock-in. From the results, it can be postulated that the change of phase difference and flow condition is responsible for the resonating behavior of the structure during lock-in.

The Effect of the Collective Reward and Punishment Marks System on Children's Adaptation to School -Focusing on the Primary-school Children in the upper Grades- (집단상벌점제가 아동의 학교적응에 미치는 영향 -초등학교 고학년 학생들을 중심으로-)

  • Lee, Hyun-Sook
    • The Journal of the Korea Contents Association
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    • v.13 no.4
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    • pp.518-528
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    • 2013
  • A number of schools have introduced the Reward and Punishment Mark System. It has been applied to children at school in order to minimize the ill effects that are often caused by physical punishment. In this case, teachers have caused problematic issues in the course of student life guidance at school. However, the application of the personal Reward and Punishment Mark System raises many other questions as well. Accordingly, there is the necessity of making up for its weak points on the systematic level. The purpose of this study is to understand the Effect of the Collective Reward and Punishment Mark System, as a substitute punishment to the physical punishment, applying the reward and punishment mark system not to an individual but to a group. The Collective Reward and Punishment Mark System for the upper grade students of primary schools showed a positive effect which assists their adaptation to school. To put it more concretely, according to the characters of the study subjects, the system has proved that boy students are more positively affected than girl students. It has been also revealed that those students in the fourth grade experience a positive change in all areas of the adaptation to school, while those in the fifth and the sixth grade were negatively affected. Moreover, those who hold a lower rank in respect of grade achievement experienced a more positive change than those standing among a high rank. It is expected that the Effect of the Collective Reward and Punishment Marks System, on the basis of the study, possesses affirmative intervention on the field.

A Research on Trust Realization Strategies for Oriental Medical Quality Improvement (한방의료 품질 향상을 위한 신뢰구현 체계구축 연구)

  • Kim, Hyun Ji;Kim, So Youn;Ji, Young Seung;Nam, Seung Kyu;Kim, Jeong Ho;Kim, Young Il
    • Journal of Acupuncture Research
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    • v.31 no.1
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    • pp.75-93
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    • 2014
  • Objectives : This study was designed to establish medical trust realization system by finding factors influential to it using questionnaire. Methods : 277 subjects were participated in this study. After a treatment, we conducted a survey from April 1st to October 31th about medical service perception index, medical trust index, patient satisfaction index, patient reliability index, patient flow degree index, recall intension index, and hospital image index. To evaluate the influence of medical service perception with other 6 indexes, we statistically made regression analysis of the results through the survey. Results : By the results of the analysis, evaluation of hospital image influenced all 6 indexes. The systemicity of treatment process had an effect on 5 indexes except for the flow degree of patients. The humanity of medical team brought out the estimation of 4 indexes except for the patient flow degree and hospital image. The empathic ability of doctor and appropriacy of medical costs hold the next rank influencing 3 indexes. It reached the conclusion that the systemicity of medical team tend to determine the medical trust and patient reliability. The expertise, professional skill of doctor, the fault, commercial application, fame of medical team, the speed of treatment process, the newest and clean medical facility affected each one index. Conclusions : Korean medicine should find a way to consider the mind of patients for improving the medical quality through trust realization system, keeping up with times. As a result of this research, we can find out important causes which influence the trustful medical system. From now on, we should apply this result to actual treatment of psychology customized system. Also, more simple and clear questionnaire was organized through this research, it can be used to forward research to apprehend patient mentality more conveniently.

A Study on Harmonized Hand Signal Standards for Shipboard Work Safety (1): A Validity Analysis of Ship Hand Signal Standardization (선박작업 안전을 위한 수신호 통일지침 마련에 관한 연구(1) - 선박의 수신호 체계 표준화 타당성 검증을 중심으로)

  • Kim, Joo Hwan;Jo, Min Chul;Kim, Yong Nam;Choi, Choong Jung;Kim, Hwa Young
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.1
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    • pp.47-55
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    • 2017
  • As preliminary work for the establishment of a harmonized ship hand signal standard, this paper explores the availability of hand signals as a means of shipboard work communication and considers the validity of standardization. Prior to the feasibility study, shipboard work activities that use hand signals were classified based only on ship safety managers' arbitrary decisions. This survey was carried out to measure shipboard workers' willingness to communicate with hand signals and their preferences regarding the institutional standardization of a hand signal framework if they engage in activities classified as relevant. The results of statistical analysis (a t-test and correlation analysis) showed that respondents are willing to accept harmonized hand signals regardless of both their work type (crew/safety supervisors) and work department (deck/engine room) under working situations where hand signals are an available means of communication. In addition, there was a significant difference in the extent of shipboard workers' frequency of hand signal usages between each type of work activity, indicating a significant positive (+) correlation between frequency of usage and preference for standardization. Finally, it was concluded that shipboard work communication would be effectively improved if a follow-up study is carried out to establish prioritized harmonized hand signal standards for port-related work activities, such as crane operation, windlass/winch operation, line movement/delivery and cargo hold operations.

A Study on The Fruits Mentioned in the Bible (성서에 언급된 과실에 관한 연구)

  • Kim, Sung-Mee;Lee, Kwang
    • Journal of the East Asian Society of Dietary Life
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    • v.9 no.2
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    • pp.149-160
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    • 1999
  • This paper is intended to find out what kinds of fruits are mentioned in the Bible and how they were used in those days. It has also analyzed in what terms they are expressed in the Korean Version of the Bible and studied agricultural regulations involved in the religion, and allegorical uses of the fruits. Olives were the primary fruit in the economy of the ancient times, followed by figs and vines. In addition, there are mentioned in the Bible almonds, apples, dates. mulberries and pomegranates. Olive trees have been grown for more than six thousand years. The Hebrew word. Zayit is mentioned in the Bible more than fifty times. Olive trees are not so beautiful in themselves but as they give us humans abundant reap and a lot of oil, they have been thought to be beautiful. Olive trees grow well on the seaside in the salty air and fog. Vines began to grown as early as in the Bronze Age(the period of 3000 to 2000 B.C.). In Northern Greece, grape seeds were found to belong to the year 4500 B.C. or so. The vine gardens produced raisins and wine as well as vines. Figs are the fruit which are first mentioned in the Bible(Genesis 3:7) and they were the precious product of the Palestine people, which is described in Deuteronomy 8:8. Figs are sweet and watery and can easily quench thirst on hot summer days. They were used for cookies and wine in the raw or dried state. An apple, which is tappuah in Hebrew, is mentioned as 'Sagwa' six times in the Revised Korean Version, and in the Korean Joint Version it is twice mentioned as 'Sagwa' and as 'Neungum' four times. In ASV and KJV, 'apple' appears eleven times. which is because' the apple of eye' is translated in the 'Nun-dong-ja(the pupil of the eye)'In the Korean Version. 'Sagwa(apple)'of Proverb 25:11, the Song of Songs 2:3, 2:5, 7:8, 8:5 and Joel 1 :12 have been thought to be doubtful. because apple trees cannot be grown in the areas mentioned in the Bible. Some maintain that the apples in the Bible refer to apricots(Prunus armeniaca, Citrus medica L.) or golden oranges (Citrus sinensis L. Obsbeck) which is confusing. In the Revised Korean Version, 'Salgu(apricots)' appears eight times while ASV and KJV translate almond into 'Salgu'. So since translating a genuine apricot into 'Salgu' can be confusing, a great care should be taken in the translation into Korean. Some hold that as some papyri arround the year 1200 B.C. describes pomegranate, apple, olive and fig trees growing on the Nile delta, tappuah rightly refers to 'Sagwa(apple)' In the Korean Joint Version, Sagwa and Neungum are used together to refer to the same fruit, which should be avoided. It is desirable to use the same word for the same thing. Sagwa' showing up six times In the HeL.Ised Korean Version should all be replaced by 'Neungum' Dates symbolized peace and abundance were used for food in the raw or dried state, and were made into honey. Pomegranates can be eaten in the raw state and be used for sherbets and wine. Juice made of promegranates can be mixed with wine and drunk.

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The Implications of Increasing Safety and Environmental Standard for Ship Operators

  • Marsh, Captain A.G.
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.2 no.1
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    • pp.137-150
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    • 1996
  • Safety is built in to the activities of the prudent ship operator. Ant investment made towards this end is likely to have a measurable payback in positive terms. That there must be an investment is inevitable, because the industry at large has let things slip too far too long. Those who have not allowed it to slip too far and who are the first to recognize that safety, far from costing money, in the long term actually preserves it, will be wieners. Too many seem to have lost sight of the fact that every one hundred pennies saved is a full one hundred pennies profit. Every hundred pennies of additional revenue contributes no more then fifteen pence to profit. Environmental protection is not so simple, nor so financially attractive. Man needs the minerals of the Earth as well as the products of the soil and sea survive. We(the human race) are still not in the position, politically or financially to manage the Earth's assets without causing damage. The evidence of our damage is evident in many different parts of the Glove and will in some cases haunt several generations still to come. We have learned a lot, and continue to learn, but despite the best intentions some Government needs for their people will be at the expense of people in another region for the foreseeable future. We sailors ply the seas with the raw materials of commerce as well as the finished and part finished goods. It does not always sit well to consider too deeply what effect the ship and the cargo it carries is having, or may have, on some communities, or on the sea through which sail. None my generation can hold up his head and claim to be without blame in the pollution of the seas. Times are changing though, and Governments are turning their attention more to the protection of our planet and its precious resources. This will not be without cost. The investment will have to be made not for our benefit, but for the benefit of generations yet to come, however the cost will have to be borne by society as a whole, not by the shipping community alone. The debate surrounding the choice between engineering our way to a better tomorrow, or adapting our working practices will continue. Each method has the same goal as its target and as long as we attain the goal does it really matter how we get there?

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Hydrodynamic Properties of Interconnected Fluidized Bed Chemical-Looping Combustors (상호 연결된 유동층 매체 순환식 연소로의 수력학적 특성)

  • Son, Sung Real;Go, Kang Seok;Kim, Sang Done
    • Korean Chemical Engineering Research
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    • v.48 no.2
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    • pp.185-192
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    • 2010
  • The chemical-looping combustion(CLC) has advantages of no energy loss for separation of $CO_2$ without $NO_x$ formation. This CLC system consists of oxidation and reduction reactors where metal oxides particles are circulating through these two reactors. In the present study, the reaction kinetic equations of iron oxide oxygen carriers supported on bentonite have been determined by the shrinking core model. Based on the reactivity data, design values of solid circulation rate and solids inventory were determined for the rector. Two types of interconnected fluidized bed systems were designed for CLC application, one system consists of a riser and a bubbling fluidized bed, and the other one has a riser and two bubbling fluidized beds. Solid circulation rates were varied to about $30kg/m^2s$ by aeration into a loop-seal. Solid circulation rate increases with increasing aeration velocity and it increases further with an auxiliary gas flow into the loop-seal. As solid circulation rate is increased, solid hold up in the riser increases. A typical gas leakage from the riser to the fluidized bed is found to be less than 1%.

A New Mode Changable Asymmetric Full Bridge DC/DC Converter having 0 ~ 100 % Duty Ratio (0 ~ 100 % 시비율을 갖는 새로운 모드 가변형 비대칭 풀 브리지 DC/DC 컨버터)

  • Shin, Yong-Saeng;Roh, Chung-Wook;Hong, Sung-Soo;Han, Sang-Kyoo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.15 no.2
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    • pp.103-110
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    • 2010
  • In this paper, a new mode changeable asymmetric full bridge dc/dc converter is proposed to solve the freewheeling current problem of the conventional zero voltage switching(ZVS) phase shift full bridge(PSFB) dc/dc converter of low output voltage and high output current applications. The proposed converter is operated as an asymmetric full bridge converter when the duty cycle is less than 50% and active clamp full bridge converter when the duty cycle is greater than 50%. As a result, since its freewheeling current is eliminated, the conduction loss is lower than that of the conventional ZVS PSFB dc/dc converter. Moreover, ZVS of all power switches can be ensured along a wide load ranges and output current ripple is very small. Therefore, high efficiency of the proposed converter can be achieved. Especially since its operation mode is changed to the active clamp full bridge converter during hold up time and can be operated with 50~100% duty ratio, it can produce the stable output voltage along wide input voltage range. The operational principles, theoretical analysis and design considerations are presented. To confirm the operation, validity and features of the proposed converter, experimental results from a 1.2kW($400V_{dc}/12V_{dc}$) prototype are presented.