• Title/Summary/Keyword: Large vessel

Search Result 668, Processing Time 0.026 seconds

Design of a ship model for hydro-elastic experiments in waves

  • Maron, Adolfo;Kapsenberg, Geert
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.6 no.4
    • /
    • pp.1130-1147
    • /
    • 2014
  • Large size ships have a very flexible construction resulting in low resonance frequencies of the structural eigen-modes. This feature increases the dynamic response of the structure on short period waves (springing) and on impulsive wave loads (whipping). This dynamic response in its turn increases both the fatigue damage and the ultimate load on the structure; these aspects illustrate the importance of including the dynamic response into the design loads for these ship types. Experiments have been carried out using a segmented scaled model of a container ship in a Seakeeping Basin. This paper describes the development of the model for these experiments; the choice was made to divide the hull into six rigid segments connected with a flexible beam. In order to model the typical feature of the open structure of the containership that the shear center is well below the keel line of the vessel, the beam was built into the model as low as possible. The model was instrumented with accelerometers and rotation rate gyroscopes on each segment, relative wave height meters and pressure gauges in the bow area. The beam was instrumented with strain gauges to measure the internal loads at the position of each of the cuts. Experiments have been carried out in regular waves at different amplitudes for the same wave period and in long crested irregular waves for a matrix of wave heights and periods. The results of the experiments are compared to results of calculations with a linear model based on potential flow theory that includes the effects of the flexural modes. Some of the tests were repeated with additional links between the segments to increase the model rigidity by several orders of magnitude, in order to compare the loads between a rigid and a flexible model.

Study on the clinical application of Iridological Constitution to the Gynecological disease diagnose (홍채(虹彩) 체질(體質)의 부인과(婦人科) 임상(臨床) 응용(應用)에 관(關)한 연구(硏究) -불임, 자궁근종, 난소낭종 환자를 중심으로)

  • Lee, Bo-Ra;Lee, Jung-Eun;Jung, Jin-Hong;Yoo, Dong-Youl;Park, Kyung-Mi
    • The Journal of Korean Obstetrics and Gynecology
    • /
    • v.15 no.4
    • /
    • pp.136-148
    • /
    • 2002
  • This study was performed to investigate the relation between Iridological constitution and Gynecological disease. Iris is one of the most complicated part of our bodies. It reflects perfectly organ's status, toxic accumulation, person's characteristics and healing effects. Many signs of Iridology were closely researched to examine the relation between Iridology and disease. After studying these matters, we could find that lacuna and auto-nerve wreath are intimately related. Especially the portions of auto-nerve wreath loss are accorded with the organ's present illness. Most of patients have scurf ring and vessel congestion sign. Large Intestine's structure also shows us the meaningful result that ballooned is the most common, spasticity and stricture are next. Connective tissue weakness constitution is 39.22%, complex 35.29% and blood-originated 25.49%. According to the three-step constitution by the Genetic facter, average type is 52.94%, weak type 35.29% and strong type 11.76%. Above these results, we can reach a conclusion that Iridological constitution are intimately related with Gynecological disease. And further study are requested to get a objectivity in a Gynecological diagnose. Iridology is a bright prospective study and interesting diagnostic method. If we deeply investigate this science, before long we can have a great outcome and more objective diagnostic skill.

  • PDF

Analysis of 363 Consecutive Patient with Acute Ischemic Stroke f개m the Hanbang Stroke Registry (뇌혈관 한의학 기반 연구사업 등록자료를 통한 363명의 급성기 뇌경색 환자의 기초 임상자료 분석)

  • Sun, Jong-Joo;Jung, Jae-Han;Moon, Sang-Kwan;Cho, Ki-Ho;Ko, Seong-Gyu;Chen, Chan-Yong;Han, Chang-Ho;Jung, Woo-Sang
    • The Journal of Korean Medicine
    • /
    • v.28 no.1 s.69
    • /
    • pp.35-41
    • /
    • 2007
  • Objectives : To gain better insights on the characteristics of stroke patients admitted to oriental medical hospitals, we analyzed the data of 363 consecutive patients with acute ischemic stroke from Hanbang Stroke Registry supported by the Ministry of Science and Technology of Korea. Methods : Subjects' enrollment was in the oriental medical hospitals of 3 universities located in the metropolitan region from October 2005 to October 2006. We assessed the subjects' general characteristics, risk factors, and etiology of stroke. Each patient's TOAST classification type was confirmed by two independent specialists. Those were small vessel occlusion (SVO), large artery atherosclerosis (LAA), cardioembolism (CE), stroke with other determined etiology (SOE), and stroke with undetermined etiology (SUE).Results 'The distribution of the subjects' general characteristics and risk factors for stroke were similar with result storm previous reports. However, in the TOAST classification, SVO was the major type occupying 78.5% in the total subjects, which is the highest share compared with other research with similar methods. These results imply that patients with more severe symptoms rarely visit oriental medical hospitals. Conclusion : Assuming that this research will continue adding patient's data continuously, this work will help us to understand the features of stroke patients at oriental medical hospitals, and contribute to expansion of the Korean Hanbang Stroke Data Bank.

  • PDF

Generating Tool for Visualization System in Real-time Field Monitoring (실시간 현장 감시를 위한 가시화 시스템 생성 도구)

  • Park, Bokuk;Tak, Haesung;Lee, Chae-Ho;Cho, Hwan-Gue
    • The Journal of the Korea Contents Association
    • /
    • v.14 no.9
    • /
    • pp.54-63
    • /
    • 2014
  • It is general that the field plant is too large to be monitored by human works. So it is crucial to prepare one automated monitoring system to prevent unexpected accidents in advance. However, most of previous monitoring systems were to be implemented by human programmer independently, so the total developing cost of a set of similar monitoring systems is so high. In order to overcome this disadvantage, we propose a new specification language for meta-description of monitoring system. Also we propose a generation tool for monitoring system with the input meta-description files. Using these meta-description files, we show it is so fast and effective to get a new monitoring system for a specific field plant. In experiment we have shown that our generation system work successfully in newly developing a monitoring system for the water-vessel plant.

Naval Vessel Spare Parts Demand Forecasting Using Data Mining (데이터마이닝을 활용한 해군함정 수리부속 수요예측)

  • Yoon, Hyunmin;Kim, Suhwan
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.40 no.4
    • /
    • pp.253-259
    • /
    • 2017
  • Recent development in science and technology has modernized the weapon system of ROKN (Republic Of Korea Navy). Although the cost of purchasing, operating and maintaining the cutting-edge weapon systems has been increased significantly, the national defense expenditure is under a tight budget constraint. In order to maintain the availability of ships with low cost, we need accurate demand forecasts for spare parts. We attempted to find consumption pattern using data mining techniques. First we gathered a large amount of component consumption data through the DELIIS (Defense Logistics Intergrated Information System). Through data collection, we obtained 42 variables such as annual consumption quantity, ASL selection quantity, order-relase ratio. The objective variable is the quantity of spare parts purchased in f-year and MSE (Mean squared error) is used as the predictive power measure. To construct an optimal demand forecasting model, regression tree model, randomforest model, neural network model, and linear regression model were used as data mining techniques. The open software R was used for model construction. The results show that randomforest model is the best value of MSE. The important variables utilized in all models are consumption quantity, ASL selection quantity and order-release rate. The data related to the demand forecast of spare parts in the DELIIS was collected and the demand for the spare parts was estimated by using the data mining technique. Our approach shows improved performance in demand forecasting with higher accuracy then previous work. Also data mining can be used to identify variables that are related to demand forecasting.

Numerical Representation of Hull Form Using Modified Cubic Spline (Modification Cubic Spline에 의한 선체형상의 수치적 표현)

  • W.S.,Kang;K.Y.,Lee;Y.C.,Kim
    • Bulletin of the Society of Naval Architects of Korea
    • /
    • v.27 no.1
    • /
    • pp.3-10
    • /
    • 1990
  • Hull form can be described numerically by two approaches, one is to describe a hull form with a set of curves("curve approach"), and the other is to describe it with surfaces directly("surface approach"). This paper describes the numerical definition scheme of hull form using curve approach method which defines the hull form by a set of curves consisting of 2-dimensional transverse section curves and 3-dimensional longitudinal curves. A set of curves in the hull form definition scheme is described by the modified cubic spline which modified the general parametric cubic spline in order to ensure a very smooth curvature distribution within the curve segment even though a curve segment has large tangent angle at its end points. Illustrative examples are given showing the application of the method to represent the hull form of SWATH ship and oceanographic research vessel. Also, examples for hull form transformation are shown by using this method connected with transformation technique.

  • PDF

A Study on the VLCC's Handling to Avoid Heavy Weather ofthe North Pacific in Winter. (동계 북태평양을 항행하는 대형선박의 황천피항조선에 관한 연구)

  • 민병언;정명선
    • Journal of the Korean Institute of Navigation
    • /
    • v.8 no.2
    • /
    • pp.51-70
    • /
    • 1984
  • In the North Pacific Ocean a lot of large waves set up in winter, affected by continued winds and swells owing to severe extratropical cyclones. Under this sea condition, if the ship is about 100,000L/T (in deadweight capacity tonnage), we can't find the danger involved in the ship at sea apparently. But when we compare the seaworthiness of ship's building strength with the stress given to the hull by waves, we can't insist that the former be more stronger than the latter. As a result, VLCC is in danger of destroying and cutting for lack of longitudinal strength in heavy weather. Up to this time, Naval Architects have actively studied the relation between ship's longitudinal strength and waves as a ship's projector; however, actually, they have never made more profound study on the problem of longitudinal strength in relation to navigation. The main puprpose of this thesis is to clarify these vivid actual states of ship's trouble unknown to ship's masters. In this thesis we picked up VLCC Pan Yard, a vessel of Pan Ocean Bulk Carrier company's, as a model ship. And in the North Pacific Ocean, we have chosen for this research the basins where the wind speed and the wave height are greater than average. The data used this thesis are quotes from the "winds and waves of the North Pacific Ocean('64-'73)", and wind speed more than 30 knots was made use of as an ocject of this study. By usinh the ITTC wave spectrum, we found out the significant waves for every 5 knots within the range of 20 knots to 45 knots of wind speed. According to this H1/1000 was calculated. The stress of ship's hull is determined by ship's speed and wave height. We compared the ship's longitudinal strength with a planned wave height by rules of several famous classification societies in the world. In the last analysis, we found out that ship's present planned strength in heavy weather is not enough. Finally we made a graph for avoiding heavy weather, with which we studied safe ship's handling in the North pacafic Ocean in winter.

  • PDF

A Comparative Study for the Fatigue Assessment of Side Shell Longitudinals on 8,100 TEU Container Carrier using Hot Spot Stress and Structural Stress Approaches (구조응력 및 핫스팟 응력을 이용한 8,100 TEU 컨테이너선 선측 종늑골구조의 피로 강도 평가에 대한 비교 연구)

  • Kim, Seong-Min;Kim, Myung-Hyun;Kang, Sung-Won;Pyun, Jang-Hoon;Kim, Young-Nam;Kim, Sung-Geun;Lee, Kyong-Eon;Kim, Gyeng-Rae
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.45 no.3
    • /
    • pp.296-302
    • /
    • 2008
  • Recently, a mesh-size insensitive structural stress definition (structural stress method) is proposed that gives a stress state at weld toe with a relatively large mesh size. The structural stress definition is based on the elementary structural mechanics theory and provides an effective measure of a stress state in front of weld toe. In this study, a fatigue strength assessment for a side shell connection of a container vessel using both the hot spot stress and the Battelle structural stress method was carried out. A consistent approach to compute the extrapolated hot spot stress for design purpose is described and current fatigue guidance is evaluated. Fatigue strength predicted by the two methodologies, e.g. hot spot stress and structural stress approaches, at hot spot locations of a typical ship structure are compared and discussed.

A STUDY ON THE PRE-AND POST-IRRADIATION EFFECT OF BLOOD VESSELS IN THE EXPERIMENTALLY INDUCED TONGUE CANCER (실험적 설암에서 방사선 조사전후의 혈관분포에 관한 연구)

  • Kim Young-Tae;Park Tae-Won
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
    • /
    • v.20 no.1
    • /
    • pp.41-49
    • /
    • 1990
  • The author observed the changes of vasculature of pre-and post-irradiation on DMBA induced rat tongue cancer. The study was performed by using vascular corrosion resin casting, and scanning electron microscopy. The results were as follows. 1. The capillaries runned parallely and formed bundles and, sometimes, plexus. The endothelial cells were arranged regularly and small pores were observed. 2. In irradiated normal tongue the capillaries were curved slightly and formed plexus on initial day of post-irradiation. On third day the capillaries and capillary pores were dilated and the endothelial cell arrangement was irregular. The effects of irradiation were gradually increased from initial to the 3rd day, though it was decreased after 7th day. 3. The vasculature of DMBA induced tongue cancer group were very irregular, and large avascular lesions were formed according to the cancer necrosis or tumor cell nest and the vasculature was narrowed and paralleled around the avascular lesion by compression of cancer cell nest. The vascular wall was roughened and dilated, forming club shaped or varix. 4. The vessels were curved and formed reticular network in irradiated DMBA induced tongue carinoma group. The free end of newly formed capillaries had regular width, and also irregular club shaped or aneurysmal dilatation were observed. The vascular structures were destroyed and vessels were fused in tumor necrosis lesion. The radiation effects were marked on the first and third day of irradiation and the effects were decreased after seventh day and showed capillary regeneration.

  • PDF

A Case of the Bronchial Artery-Pulmonary Vein Malformation (기관지동맥-폐정맥의 동정맥기형 1예)

  • Yoo, Tae-Seok;Jo, Young-Il;Heo, Weon-Man;Jin, Choon-Jo;Song, Kwang-Seon;Yong, Suk-Joong;Shin, Kye-Chul
    • Tuberculosis and Respiratory Diseases
    • /
    • v.42 no.5
    • /
    • pp.767-771
    • /
    • 1995
  • The bronchial artery-pulmonary vein malformation should be called the systemic artery-to-pulmonary vein arterioveonus malformation in the lung. Although pulmonary arteriovenous malformation has been well documented in intrapulmonary arteriovenous malformation, the systemic artery-to-pulmonary vein arteriovenous malformation is rare. Most patients with systemic artery-to-pulmonary vein arteriovenous malformation is asymptomatic and the diagnosis of these anomaly may be done by continuous murmur or abnormal chest X-ray on the physical examination. The pathogenesis of this condition is congenital malformation which explains these anastomoses between the pulmonary vein and accessory brachial arteries and acquired malformation which explains development of new blood vessel to supply large enough to cause significant systemic-pulmonary shunts due to inflammation secondary to infection, trauma, or previous surgery. We experienced a case of the bronchial artery-pulmonary vein malformation which was detected on angiography in 20-year-old women whose chief complain is hemoptysis. This massive hemoptysis was controlled by selective brachial artery embolization with Gelfoam and Ivalon particles.

  • PDF