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A Study on the Optimum Navigation Route Safety Assessment System using Real Time Weather Forecasting (실시간 기상 정보를 이용한 최적 항로 안전 평가 시스템의 연구)

  • Choi, Kyong-Soon;Park, Myung-Kyu;Lee, Jin-Ho;Park, Gun-Il
    • Proceedings of KOSOMES biannual meeting
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    • 2007.05a
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    • pp.203-210
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    • 2007
  • This paper treats optimal route safety assessment system at seaway based on weather forecasting data through INMARSAT. Since early times, captain have been sailing to select the optimum route considering the weather, ship loading status condition and operational scheduling empirically. However, it is rare to find digitalized onboard route support system whereas weather facsimile or wave and swell chart are utilized for the officer, based on captain's experience. In this paper, optimal route safety assessment system which is composed of voyage efficiency and safety component is introduced. Optimum route minimized ETA(estimated time of arrival) and fuel consumption that shipping company. and captain are requiring to evaluate for efficient voyage considering speed loss and power increase based on wave added resistance of ship. In the view point of safety, seakeeping prediction is performed based on 3 dimensional panel method Basically, the weather forecast is assumed to be prepared previously in order to operate this system.

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A General Formula for Calculating the Value of Transverse Moment of Inertia by Observing the Roll Motion of Ships (횡요상태 관측에 의한 선체 횡관성모멘트 값의 도출을 위한 일반식)

  • Choi, Soon-Man
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.21 no.5
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    • pp.538-542
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    • 2015
  • The transverse moment of inertia is an indispensable factor in analyzing the roll motion characteristics of ships and the calculating method needs to be based on the more reasonable theories when deciding the value as the results and reliability of analysis could be much affected by the correctness. However, the mass distribution and shape of hulls are quite complicated and give much difficulties in case of calculating the value directly from the ship design data, furthermore even acquiring the detailed design data for calculation is almost impossible. Therefore some simpler ways are practically adopted in the assumption that the gyradius of roll moment can be decided by a given ratio and hull width. It is well known that the responses of the free roll decay are varied according to the value of roll moment in view of roll period and amplitude decay ratio, so that the general formula to get the moment value can be derived also from the observation of roll decay responses. This study presents how the roll period and decay ratio are interrelated each other from the roll motion characteristics with suggesting a general formula to be able to calculate roll moment from it. Finally, the obtained general formula has been applied to a ship data to check the resultant characteristics through analyzing graphs and showed that the roll moment becomes more accurate when rolling period and decay ratio are considered together in calculation.

Characteristics of Korean Inshore Fishing Boats (한국(韓國) 연근해어선(沿近海漁船)의 특성(特性))

  • Keuck-Chun,Kim
    • Bulletin of the Society of Naval Architects of Korea
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    • v.8 no.1
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    • pp.67-94
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    • 1971
  • Korean fisheries industry holds 57,255 boats amounting to 269,079 tons in gross as of the end of 1967. The boats of the size under 30G.T., about sixty-two per cent of the total in tonnage, are utilized in coastal and their contribution to the total production of Korean fisheries industry is estimated at over seventy-five percent. Hull forms and construction method of them are partly in transition stage to the western tradition from the oriental tradition, which employs the chine-type straight-framed section, and tick and wide wooden planking fastened on naturally bent timber frames. And only about a half of them are mechanized. About fifty-seven per cent, 7,525 boats amounting to 91,751 gross tons, of the coastal and inshore fishing boats are those of the size ranging 5G.T. to 30G.T., which are engaged mostly in draft-and gill-netting, angling, longlining, anchovy seining, squid fishing and set-netting. The important fishing boats forming main structure of the inshore fishing fleets can be classified as 5G.T.-class multi-purpose boats, 10G.T.-class angling/longlining boats and 20G.T.-class drift-/gill-netters mostly utilized in the east-sea, 15G.T.-class anchovy seiner in the south-sea-sea, 20G.T.- and 28G.T.-class stow-netters in the west sea. Each of the three sea regions, east, south, and west, of Korean water has distinctly different characters from one another in topography, geology and sea aspects, and consequently in marine resources, fishing grounds and fishing tactics desired. Hence, the finishing boats in each sea region have also their own characters in hull form, structural features, deck design and equipments. In this report, analyzing the characteristics of the existing inshore fishing boats ranging 5G.T. to 30G.T. in size from view points of naval architecture and engineering, the author made an integrated investigation of their characteristics, covering size and principal dimensions, hull form, deck design, structural features and mechanization, in close connection with the natural circumstances of Korean water and local techno-socio-economic problems, and, finally, made some suggestions for the rational improvement or modernization of the inshore fishing boats. Further details of the characteristics of Korean inshore finishing boats are referred to the drawings of them compiled by the author and given in the reference[23] listed at the end of this report.

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Prediction of frontal soft tissue changes after mandibular surgery in facial asymmetry individuals (안면비대칭자의 하악골 악교정수술 후 정면 연조직 변화 예측을 위한 연구)

  • Hwang, Hyeon-Shik;Lee, Jessica J.;Hwang, Chung-Hyon;Choi, Hak-Hee;Lim, Hoi-Jeong
    • The korean journal of orthodontics
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    • v.38 no.4
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    • pp.252-264
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    • 2008
  • Objective: To aid the development of a frontal image simulating program, we evaluated the soft tissue frontal changes in relationship to movement of hard tissue with orthognathic surgery of facial asymmetry patients. Methods: Preoperative and postoperative frontal cephalograms and frontal view photographs of 45 mandibular surgery patients with facial asymmetry were obtained in a standardized manner. Vertical and horizontal changes of hard tissue and soft tissue were measured from cephalograms and photographs, respectively. Soft tissue change in result to hard tissue change was then analyzed. Results: Both vertical and horizontal correlation analysis showed a weak relationship between the changes. Hard tissue points that were picked for 1 : 1 mean ratio with soft tissue points did not show any significant relevance. For each soft tissue change, regressive equation was formulated by stepwise multiple regression analysis, and the equation for soft tissue Menton was most reliable in predicting changes. Both vertical and horizontal hard tissue changes were used together in prediction of vertical or horizontal soft tissue change. Conclusions: The results suggest that computerized image simulation using regression analysis may be of help for prediction of soft tissue change, while 1:1 mean ratio method is not useful.

Cloud Messaging Service for Preventing Smishing Attack (스미싱 공격 방지를 위한 클라우드 메시징 서비스)

  • Park, Hyo-Min;Kim, Wan-Seok;Kang, So-Jeong;Shin, Sang Uk
    • Journal of Digital Convergence
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    • v.15 no.4
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    • pp.285-293
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    • 2017
  • They are rapidly evolving malicious attacks on smart devices, and to timely protect the smart devices from these attacks has become a very important issue. In particular, smishing attack has emerged as one of the most important threats on the smartphone. In this paper, we propose the cloud service that can fundamentally protect the user from the risk of smishing attack. The proposed scheme provides cloud messaging service that can filter text messages including URLs in the user's smart device, view and manage them through a virtual machine provided by a cloud server. The existing techniques for preventing smshing attacks protect only malicious code of a known pattern and there is the possibility of error such as FP(False Positive) or FN(False Negative). However, since the proposed method automatically filters all text messages including URLs, storing, viewing, and managing them in their own storage space on the cloud server, it can completely block the installation of malwares(malicious codes) on the user's smart device through smishing attacks.

The Effect of Passing Aged Years to the Polarization Characteristics of Embedded Steel Bar of Mortar Specimen(W/C:0.4) (몰타르 시험편(W/C:0.4) 내부철근의 분극특성에 미치는 재령년수의 영향)

  • Moon, Kyung-Man;Won, Jong-Pil;Park, Dong-Hyun;Lee, Sung-Yul;Jeong, Jin-A;Lee, Myeong-Hoon;Baek, Tae-Sil
    • Corrosion Science and Technology
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    • v.13 no.1
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    • pp.20-27
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    • 2014
  • The structures of reinforced concrete has been extensively increased with rapid development of industrial society. Futhermore, these reinforced concretes are easy to expose to severe corrosive environments such as sea water, contaminated water, acid rain and seashore etc.. Thus, corrosion problem of inner steel bar embedded in concrete is very important in terms of safety and economical point of view. In this study, multiple mortar test specimen(W/C:0.4) with six types having different cover thickness each other was prepared and was immerged in seawater solution for five years to evaluate the effect of cover thickness and immersion years to corrosion property of embedded steel bar. And the polarization characteristics of these embedded steel bars was investigated using electrochemical methods such as measuring corrosion potential, cathodic polarization curve, and cyclic voltammogram. At the beginning of immersion, the corrosion potentials exhibited increasingly nobler values with increasing cover thickness. However, after immersed for 5 years, the thicker cover of thickness, the corrosion potentials shifted in the negative direction, and the relationship between corrosion potential and cover thickness was not in good agreement with each other. Therefore, it is considered that the thinner cover of thickness, corrosive products deposited on the surface of the embedded steel bar plays the role as a resistance polarization which is resulted in decreasing the corrosion rate as well as shifting the corrosion potential in the positive direction. As a result, it seemed that the evaluation which corrosion possibility of the reinforced steel would be estimated by only measuring the corrosion potential may not be a completely desirable method. Therefore, it is suggested that we should take into account various parameters, including cover thickness, passed aged years as well as corrosion potential for more accurate assessment of corrosion possibility of reinforced steel which is exposed to partially or fully in marine environment for long years.

Social Readjustment Experience of Military Widows as Single Mothers (순직군인 배우자의 여성한부모로서 사회 재적응 경험)

  • Lee, Yoon-Soo
    • Korean Journal of Social Welfare
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    • v.61 no.1
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    • pp.81-107
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    • 2009
  • This study is to understand, in the view of resilience, the experience of military widows, whose husbands died while on active military duty and have lived as single mothers for a long time. This study using a qualitative research method based on Phenomenology, especially using Colaizzi's process of data analysis. 99 meaningful sentences, 26 themes, and 10 theme clusters has been categorized from the interview of 9 military widows, who has been participated a self-help group for them. The 10 theme clusters are 'denial and grief over the death of spouse', 'ambivalence over the duty of their husbands', 'acceptance of the helpless fate and arduous fight to live', 'sorrow in the social and historical context', 'responsibility and endeavoring of parenting', 'self-existential challenge', 'immanent belief system as a military widow'. 'effort to find self-identity in the outer systems', 'wish to reassure their existence', and 'to find the meaning of life after husband's dead'. These their self respect and feeling of honor have become their belief system in their life, which they have raised their children and take their responsibilities with their best effort. The self-help group has helped them to find their self-identity and has sustained emotionally healthy. This group has been also empowering them through their voices being heard to the outside society. They have made an effort which their existence is recognized by the country and the military system. The findings of this study can be used as a system to gather opinions and to provide information and program which may be accepted politically and then applicable and integrated social work service through the social support system and networking.

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The Structural Equivalence and Role Equivalence of Container Ports in Asia-Europe Container Shipping Networks (아시아-유럽 컨테이너 해운 네트워크 구성 항만의 구조적 등위성과 역할 등위성)

  • Lee, Sang-Yoon
    • Journal of Korea Port Economic Association
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    • v.32 no.2
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    • pp.105-122
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    • 2016
  • Numerous studies have evaluated the status of seaports. However, the majority of the research has approached this topic from the view-point of port capabilities, including locational advantage, infrastructure, productivity, and competitiveness. The position and/or role of a port can be understood more precisely and comprehensively by considering the interconnectivity among ports making up enormous global transportation networks. The main objective of this study is to compare the status of 82 container ports on the trunk shipping routes between Asia and Europe by applying the concepts of structural equivalence and role equivalence proposed by the social network analysis method. Network similarities and differences among competing ports in the regions are assessed by analysing their structural equivalence. Furthermore, the hierarchical structures of the ports located on the trunks between Asia and Northwest Europe and between Asia and the Mediterranean are constructed by evaluating their role equivalence. The results of this empirical research shows that Singapore and Rotterdam possess the most significant positions on the ocean corridors between Asia and Northwest Europe. Singapore also holds a leading position on the Asia-Mediterranean shipping route. Lastly, no ports located in the Middle East or Mediterranean regions have an equivalent weight to those of Rotterdam, Hamburg, Antwerp on the Asia-Northwest Europe route.

Simulation of Energy Resolution of Time of Flight System for Measuring Positron-annihilation induced Auger Electrons (양전자 소멸 Auger 전자 에너지 측정을 위한 Time of Flight의 분해도 향상에 관한 이론적 연구)

  • Kim, J.H.;Yang, T.K.;Lee, C.Y.;Lee, B.C.
    • Journal of the Korean Vacuum Society
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    • v.17 no.4
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    • pp.311-316
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    • 2008
  • Since the presence of the chemical impurities and defect at surfaces and interfaces greatly influence the properties of various semiconductor devices, an unambiguous chemical characterization of the metal and semiconductor surfaces become more important in the view of the miniaturization of the devices toward nano scale. Among the various conventional surface characterization tools, Electron-induced Auger Electron Spectroscopy (EAES), X-ray Photoelectron Spectroscopy (XPS) and Secondary Electron Ion Mass Spectroscopy (SIMS) are being used for the identification of the surface chemical impurities. Recently, a novel surface characterizaion technique, Positron-annihilation induced Auger Electron Spectroscopy (PAES) is introduced to provide a unique method for the analysis of the elemental composition of the top-most atomic layer. In PAES, monoenergetic positron of a few eV are implanted to the surface under study and these positrons become thermalized near the surface. A fraction of the thermalized positron trapped at the surface state annihilate with the neighboring core-level electrons, creating core-hole excitations, which initiate the Auger process with the emission of Auger electrons almost simultaneously with the emission of annihilating gamma-rays. The energy of electrons is generally determined by employing ExB energy selector, which shows a poor resolution of $6{\sim}10eV$. In this paper, time-of-flight system is employed to measure the electrons energy with an enhanced energy resolution. The experimental result is compared with simulation results in the case of both linear (with retarding tube) and reflected TOF systems.

A Study on the Change of Dye-ability of Cornus officinalis with Mordanting Treatment and Colorfastness (산수유의 염색성과 견뢰도에 관한 연구)

  • Bae, Kye-In;Choi, In-Ryu;Park, Kyeon-Soon
    • Journal of the Korea Fashion and Costume Design Association
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    • v.9 no.3
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    • pp.47-57
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    • 2007
  • This study focused on the properties natural dyeing and natural material and on the development of functional material for well-being in apparel industry. Comus officinalis Siebold et Zuccarini is used as natural dyeing material which had been reported that have curable effect for unbalanced immunity, geriatric diseases like urinary tract system, diabetes, hypertension, arthritis, tinnitus, hyperhidrosis and women's diseases like hypermenorrhea. And this material also has anti-cancer effect so that can restraint cancer cells. 3 kinds tester of cotton, wool and silk are dyed by boiled with each dye (flower, fruits, bark of tree) as first dyeing and dried in the shade. These testers are done by post-mordanting method. Aluminium Potassium(Alk(SO4)2), Cuprie Sulfate($CuSO4{\cdot}5H2O$), Stannous Chloride($SnCl2{\cdot}2H2O$), Ferrous Sulfate($FeCl2{\cdot}4H2O$), Titanium Sulfate 24% aqueous solution(Ti(SO4)2) are used as mordants. Dyeing results of Comus officinalis Siebold et Zuccarini flower and bark are shown as yellow color series. And dyeing result of fruits is pink color series. Silk shows the best dyeing property. As the point of view for dyeing property, Ti, Sn, Fe would be the properchoice for mordant. Following results are extracted in this study. Yellow color is resulted in dyeing with Cornus officinalis flower as non-mordanting condition. Yellowish red color is come from dyeing with Comus officinalis fruit as non-mordanting condition. Grayish yellow tone is resulted in dyeing with bark as non-mordanting condition. Orange tone color with Ti-mordanting, green tone color with Sn-mordanting and gray tone color with Fe-mordanting is resulted respectively. However light-fastness of Comus officinalis(flower, fruit, bark) is very low as 1 or 2 level in non-mordanting condition, Comus officinalis flower dyeing is turned out 3 or 4 level and fruit dyeing is 4 or 5 level, bark dyeing is 2 or 3 level with Ti-mordanting respectively. Eventually Comus officinalis fruit has the best light-colorfastness property among all of dyes. dry cleaning colorfastness of Cornus officinalis(flower, fruit, bark) is good as 4 or 5 level in Ti-mordanting condition, perspiration-colorfastness of Cornus officinalis(flower, fruit, bark) is good as 4 or 5 level in Ti-mordanting condition, With these results, this study could conclude that dye-ability, colorfastness problem is getting better after mordanting process and practical usage would be possible.

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