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This paper describes the motion characteristics and cargo handling efficiency of the Large-Scale Floating Coal Transshipment Station (LFTS). Indonesia is the main country supplying coal in the Asia-Pacific region, it is important to ensure stable coal supply to Japan. Because the topography of the seabed near East Kalimantan Island, Indonesia’s main coal production area, is shallow, it is difficult for bulk carriers to reach the coast. And then, Large-scale Floating Transposition Station for Loading Coal (hereafter LFTS) was proposed, which will be used as a transposition station between small coal barge coming down the river and bulk carriers stay offshore. By installing LFTS, improvement of coal transport efficiency is expected. As a previous study, the motion characteristics of LFTS using a catenary chain in its mooring system were grasped. However, LFTS can carry up to 500,000 tons of coal, and the draft of LFTS tends to change greatly depending on the coal loading conditions. Besides, the tidal difference in the sea area where the LFTS is installed is about 2 m, and the mounting position of the mooring system on the LFTS side moves up and down by about 10 m at maximum due to changes in the draft and tidal differences. For this reason, when the mounting position of the mooring system is in the lowest state, the mooring line is loosened and the horizontal force is reduced, and it is considered that sufficient restraining force is not exhibited. And, when the mounting position of the mooring system becomes high, the mooring line tension increases and the mooring line may break in some cases. Therefore, in this study, an attempt was made to use an elastic mooring line as a mooring system for LFTS. An elastic mooring line is a mooring line that incorporates a highly stretchable material between mooring lines that connect anchors and floating body. Even if the mooring line attached to the LFTS moves up and down, an appropriate tension always acts on the elastic mooring line, and it can be expected to suppress the oscillation of the floating body and prevent the mooring line from breaking due to excessive tension. However, elastic mooring lines are mainly used for mooring small structures such as piers and aquaculture facilities, but there are no examples where these mooring lines have been applied to structures over 500m like LFTS. Therefore, elastic mooring lines are adopted for the mooring system of LFTS, systematically calculated according to various setting conditions of elastic mooring lines, and it is grasped whether elastic mooring lines can be applied to LFTS, and the motion characteristics of LFTS moored by elastic mooring lines was also grasped.

Indonesia is the main country supplying coal in the Asia-Pacific region, and in order to secure a stable supply of coal to neighboring countries, efficient coal transportation is required. East Kalimantan Island in Indonesia is the main coal-producing area, but the sea around the island is very shallow and bulk carriers for transporting coal cannot approach the coast. And then, Large-scale Floating Transposition Station for Loading Coal (hereafter LFTS) was proposed, which will be used as a transposition station between small coal barge coming down the river and bulk carriers that stays offshore. LFTS has a two-dimensional extent, and because the bulkheads for separating coal according to quality are installed on the floating body, the rigidity is partially different, and the draft also changes greatly according to the coal loading condition. In this way, LFTS has different characteristics from Mega-Float, which was built in Japan in the late 1990s with the aim of realizing a floating airport, so it is important to clarify its structural characteristics. In order to grasp the stress distribution acting on the structural member in consideration of the influence of the interaction between the overall deformation and the local deformation of LFTS, an analysis in which the entire structure is modeled in detail is desired. However, because members such as the internal bulkheads are arranged in a complicated manner in LFTS, a model in which the entire structure is modeled in detail requires enormous calculation costs in both capacity and time, it is difficult to perform the analysis. In existing research, various models have been studied, but there remains a problem in setting boundary conditions that reproduce the interaction between global and local deformations. And then, in this paper, a new modeling method of LFTS that can be analyzed efficiently was proposed. And the occurrence of stress concentration in the structural members of the LFTS was identified by systematically changing the external force conditions such as the coal loading condition and wave load assumed during the operation of the LFTS, and performing LFTS oscillation analysis and stress deformation analysis. Furthermore, the occurrence of plastic strain due to large deformation was investigated. The stiffening method that efficiently suppresses the occurrence of plastic strain was studied for the locations where the plastic strain was identified by the above analysis. These results demonstrate the importance of modeling large floating structures with complex structures.

The Great East Japan Earthquake that occurred in Japan in 2011, an innumerable number of buildings in the coastal part of the east side of Japan suffered catastrophic damage, and medical facilities in coastal areas have become dysfunctional because of the significant damage incurred due to the tsunami. And land routes are not passable, but there are records of support activities utilizing water areas such as sea and river networks being extremely effective in such disaster conditions. Therefore, as one of the effective methods of medical support in the affected area immediately after the disaster, a Floating Medical Support System (hereafter Medi-float) on big disaster that can be accessed from the water area was proposed. In the near future, the area along the Arakawa River is expected to be seriously damaged by the earthquake directly under the Tokyo metropolitan area. Therefore, by installing a Medi-float that can perform medical support activities from the water area to the land without being damaged by an earthquake, since Medi-float performs medical support activities in cooperation with medical facilities on land area, preventable death is reduced. In previous studies, a procedure to estimate the facilities scale and select a suitable site for Medi-float practically based on GIS data such as the number of collapsed buildings in the target area, distribution of injured people due to the earthquake were presented. However, even if Medi-float is installed in the target area, it cannot be denied that there is a shortage of medical facilities. In consideration of smooth transportation outside the region and cooperation with surrounding medical facilities, it is hoped that a concrete and realistic medical support system by Medi-float will be established. Therefore, in this study, in order to grasp the time it takes for the injured to be transported to the medical facility and the congestion status of the medical facility, the target area was divided into 250m meshes and a time-series simulation was performed. Specifically, the distribution of injured people during a disaster was calculated on a mesh basis from the number of buildings collapsed and the number of fires. And the transport time of the injured people is calculated from the distance between each mesh and the medical facility, the movement of the injured people in consideration of the congestion status of the medical facility was simulated, necessity of cooperation between medical facilities and wide area transportation was clarified, the effect of Medi-float, which is active in the disaster area, was also evaluated.

Indonesia is a main country supplying coal in the Asia-Pacific region, it is important to ensure a stable coal supply to Japan. Because the topography of the seabed near East Kalimantan Island, Indonesia’s main coal production area, is shallow, it is difficult for bulk carriers to reach the coast. Therefore, Large-Scale Floating Coal Transshipment Station (LFTS) was proposed, which will be used as a relay base between coal-barging barges from land and bulk carriers offshore. Installing an LFTS offshore from East Kalimantan is expected to improve coal transport productivity. LFTS can store coal equivalent to five times the capacity of one bulk carrier (total 500,000T), and can accommodate 2 bulk carriers at the same time during offloading. The scale of LFTS is 590m × 160m. The LFTS has a flat spread and the elastic behavior becomes the dominant Structure. The upper part of the LFTS is different rigidity partly because the partition wall to be loaded by dividing the coal into each quality is provided. Loaded coal not only changes the draft of the LFTS but also greatly deforms the LFTS and is expected to cause local stress concentration on the structural members. Therefore, this paper investigates wave response characteristics and stress characteristics with the coal loading of the LFTS, and then evaluation of structural strength by limit state design method. In this study, linear potential theory and the finite element method (FEM) were used to analyze the static hydroelastic motion under various coal loading condition and wave response of LFTS. And, to grasp the local stress concentration occurring inside the LFTS by using the response results, a detailed model modeling a complicated internal structure was prepared. Zooming analysis which is a method of giving the deformation result by the whole model of LFTS as forced displacement to the local detailed model was carried out. As a result, depending on the coal loading condition and wave conditions, it became clear that LFTS will be in a tough situation.

In 2011, Japan experienced a major catastrophe: The Great East Japan Earthquake and subsequent tsunami. After the tsunami struck, overland transport routes were cut off, and consequently, emergency supplies and people requiring medical attention could not be transported very efficiently. Many hospitals and other emergency facilities were destroyed or were operating with reduced capabilities during this period, meaning victims could not receive treatment within a reasonable timeframe. Therefore, we need to consider emergency facilities, particularly for medical support, which are resilient and versatile for use in such situations. Floating bases for disaster relief and support ships are already available for deployment along coastal regions or on rivers near affected areas. A medical support floating base has also been proposed, which is called the Medi-float hereafter, in preparation for the anticipated Tokyo Inland Earthquake. And it is determined that the primary function of this Medi-float should be as a dialysis treatment center during normal operation and primarily for the treatment of crush syndrome patients during a disaster. But the original proposal was deemed inadequate in terms of facility scale and selection of the suitable site of Medi-float. Therefore, in this research aiming at realization of Medi-float, firstly the number of people who develop crush syndrome in the target area is estimated by GIS based on the damage prediction of the huge earthquake striking Tokyo and the risk of building collapse. Based on the distribution of dialysis treatment facilities and data such as road network data in Tokyo, Voronoi diagrams were created using GIS. And facility scale required for Medi-float and suitable installed site were examined by the distribution of crushed syndrome patients obtained by analysis and Voronoi diagram.

This paper describes characteristics of motion responses and tether tensions of a floating structure with four moon pools, on which one or two vertical axis wind turbines are installed. In this study, the authors proposed a twin-VAWT installed floating system, which was a pontoon based structure. However four moon pools were set on. The study conducted model experiments in a wave tank using regular waves with 0.6 to 2.0 seconds in wave periods and 0.02 and 0.04 m in wave height. The model had four moon pools and was installed with one or two vertical axis turbine models. From it, gyroscopic moment effects were investigated. Besides, the study performed numerical calculations with the linear potential theory based method which were a Green function method. As a results, responses of the twin-turbine model are not affected by gyroscopic moment. The study discusses motion responses and tether tensions with nonlinear behaviours from mainly the experimental results.

The large-scale tsunami generated by the Great East Japan Earthquake on March 11, 2011 caused a great deal of damage. In addition to tsunami hydrodynamic forces, loads generated by drifting objects such as ships and cars can cause destruction in coastal areas. As such, impact forces due to collisions of drifting objects are an important consideration in the design and planning of structures in coastal areas. Depending on the size of the drifting object, it is difficult to evaluate the effect of the impact force at the time of collision through tank experiments. Therefore, it is necessary to develop a numerical simulation method that can reasonably evaluate such effects. Such a method must consider the nonlinear interactions among drifting objects, a fluid, and fixed structures. In the present study, we used the moving particle semi-implicit (MPS) and finite element methods to calculate the effect of collisions between drifting objects and structures, and then verified the results experimentally. The MPS method was applied to calculate the loads and pressures due to the collisions. These results were then used to simulate the deformation of the structure using the finite element method. A tank experiment was then conducted in order to confirm the accuracy of the numerical calculations. The deformation of a rod-shaped steel structure was measured following collision with a floating acrylic plate. The experimental results confirmed the accuracy of the numerical calculations.

This paper describes the motion characteristics and cargo handling efficiency of the Large-Scale Floating Coal Transshipment Station (LFTS). Indonesia is a main country supplying coal in the Asia-Pacific region, it is important to ensure a stable coal supply to Japan. Because the topography of the seabed near East Kalimantan Island, Indonesia’s main coal production area, is shallow, it is difficult for bulk carriers to reach the coast. Therefore, LFTS is proposed, which will be used as a relay base between coal-barging barges from land and bulk carriers offshore. By installing LFTS, improvement of coal transport efficiency is expected. In considering feasibility of the LFTS system, it is important to know the cargo handling operation rate in the target area, LFTS can load 500,000 tons of coal and the draft will fluctuate greatly depending on the loading condition of coal. Therefore, when the draft is shallow, the freeboard becomes large and resonates with long-term component of the wind load and when the draft is deep, the wave force and fluid force including the slowly varying wave drift force affect the fluctuation. Also, LFTS and bulk carrier are large-scale structures, the fluid forces acting on both affect each other, so the influence of hydrodynamic mutual interference between two floating bodies cannot be ignored. In this study, fluid analysis in consideration of the hydrodynamic mutual interference of LFTS system is conducted. And, response analysis of LFTS and a bulk carrier in irregular wave which considered compound external forces such as wave load and slow varying wave drift force, wind load, tidal current was performed. As a result, it was confirmed that the motion response of LFTS was not upset because LFTS was large. Therefore, without considering the motion response of the LFTS, the cargo handling efficiency is calculated from the response analysis results of the bulk carrier and the oceanic condition of the setting sea area. As a result, the cargo handling efficiency is satisfied in the state where bulk carrier is installed leeward of LFTS, and it was confirmed that the LFTS system could be operated satisfactorily if the installation was appropriate.

Japan imports coal from Indonesia, the main coal supplier in the Asia-Pacific region. Effective and efficient movement of coal down the Markham River in East Kalimantan, Indonesia, and onto bulk carriers is challenging because the river is shallow and generally cannot accommodate bulk carriers. The primary transportation system comprises small barges that are shuttled back and forth between the inland barge ports along the river and bulk carriers offshore. This system is very time-consuming. This paper proposes a large-scale floating coal transshipment station (LFTS) for loading, storing, and offloading coal. It will act as a relay base for barges and bulk carriers. Installing an LFTS offshore from East Kalimantan is expected to improve coal transport productivity. The proposed LFTS can store 5 times the capacity of one bulk carrier and can accommodate 2 bulk carriers at the same time during offloading. The LFTS is compartmentalized by bulkheads to segregate coal according to quality. This paper discusses LFTS static stability and its elastic deformation characteristics during coal loading operations. In this study, linear potential theory and the finite element method (FEM) were used to analyze the LFTS static hydroelastic motion. Due to the compartments, coal loading conditions can vary significantly and affect the local static deflection, so we modeled the overall deformation and rigidity under various operational scenarios. The results were compared to the allowable material stress to identify conditions that will produce material failure. Moreover, we evaluated operation in the shallow Kalimantan River, since the weight of loaded coal deepens the LFTS draft, reducing the clearance between the LFTS and sea bed. We found that this reduced clearance and large added mass impact the natural frequency of the LFTS.

The damage investigations that followed the Great East Japan Earthquake revealed that automobiles, shipping containers, and even ships themselves had been caught up in the resulting tsunami before being hurled into various port facilities, causing immense damage. The damage characteristics of such collisions must be an integral part of disaster mitigation measures aimed at reducing damage due to drifting ships. When considering the impact force of massive vessels on port facilities, it is necessary to take into account the changes in the drift velocity of the vessels due to waves reflected from the facilities and other coastal structures. In previous studies, the moving particle semi-implicit (MPS) method has been adopted to examine cascading tsunami flotsam damage by means of numerical simulations. In the present study, we use the MPS method to examine the drifting behavior and impact force of ships moored to an actual harbor, taking into account waves reflected from coastal area structures. Based on the results, we discuss the applicability of this method to disaster mitigation measures.

In this study, we propose color images with color enhancement for congenital red–green color deficiency on the basis of the model proposed by Mochizuki et al. [In Terrassa, Spain: Proceedings for CGIV, Springfield VA: IST208–213] with the aim of facilitating color customization in displays used by color-deficient observers. Three types of color enhancements for deficiency were addressed in this study: colors were enhanced along the protan confusion line (i.e., P-enhancement), deutan confusion line (i.e., D-enhancement), and a line between the protan and deutan confusion lines (i.e., mix-enhancement). We investigated the color-enhanced image that is most preferred by each group of protan, deutan, and normal observers. Protan and deutan in this study indicate observers that are both dichromats and anomalous trichromats. Nine protan, nine deutan, and six normal observers participated in the experiment. The results showed that among the three types of color enhancements, the D-enhancement provided the best performance for protan observers. For deutan observers, all three types provided effective enhancement, although the P- and mix-enhancements were slightly better than the D-enhancement. Our results indicated that color enhancement increases the preference evaluations of protan and deutan observers. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 234–251, 2014; Published Online 20 February 2013 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/col.21795

This paper proposes a large-scale floating coal stockyard (LFCS) and discusses its elastic behavior. Indonesia has recently become the main country supplying coal in the Asia-Pacific region. However, there is concern that export to Japan will decrease as coal demand increases. Therefore, the trend of coal transport in Indonesia is a very important matter in ensuring the continued stable import of coal to Japan. It is difficult for bulk carriers to traverse the shallow terrain of the seabed of the Markham River in East Kalimantan to reach coastal areas. Additionally, an LFCS can be operated as a relay base for barges, and large coal carriers have been proposed for use in offshore areas. The LFCS is capable of loading, storing, and offloading coal. Installing an LFCS offshore Kalimantan is expected to improve coal transport productivity in the region. Under such circumstances, the design plan proposed in this paper can simultaneously perform independent loading and unloading without interference. The partial mass distribution and local rigidity of the LFCS varies depending on the coal loading conditions. In addition, because the structure has a planar shape, the response of the LFCS showed elastic behavior. Design example of such a huge floating structure with the great difference of the displacement is unparalleled, it is very important to clarify a design fundamental subject. The objectives of this study are to provide a preliminary LFCS design and investigate the impact of varying the mass distribution and local rigidity on not only the distribution of the distortion and internal stress but also on the dynamic hydroelastic motion of the LFCS when it is impacted by waves. Therefore, the wave response of the LFCS was analyzed under different loading conditions.

This paper presents a feasibility study for a floating medical support system, and describes its basic concept with regards to the installation location, its primary function and patient capacity. In 2011, Japan experienced a major catastrophe: the Great East Japan Earthquake and subsequent tsunami. After the tsunami struck, overland transport routes were cut off, and consequently emergency supplies and people requiring medical attention could not be transported very efficiently. Many hospitals and other emergency facilities were destroyed or were operating with reduced capabilities during this period, meaning victims could not receive treatment within a reasonable timeframe. Therefore, we need to consider emergency facilities, particularly for medical support, which are resilient and versatile for use in such situations. Floating bases for disaster relief and support ships are already available for deployment along coastal regions or on rivers near affected areas. A medical support floating base has also been proposed, which is called the Medi-float hereafter, in preparation for the anticipated Tokyo Inland Earthquake. The original proposal was deemed inadequate in terms of its choice of deployment area, and its maximum capacity for patients. The objectives of this paper are to decide the Medi-float’s primary function, the location where it should be installed, and to determine its capacity and a floor plan which adheres to the relevant regulations. It is determined that the primary function of the Medi-float should be as a dialysis treatment center during normal operation and primarily for the treatment of crush syndrome patients during a disaster. A location in Sumida ward is chosen for the installation area. In the floor plan, the Medi-float has 55 beds in dialysis treatment rooms. Also, there are areas of open space in the Medi-float to be used for coordinating the distribution of emergency supplies. The maximum capacity for patients is approximately 5,300 people, and the Medi-float can treat up to 130 patients with crush syndrome every 2 days. There is estimated to be around 106 patients with crush syndrome around the installation area in the event of a major earthquake. Therefore, this study clearly demonstrates the usefulness of the Medi-float.

Indonesia has recently become the world's second largest exporter of coal, and a great deal of coal is supplied to the Asia Pacific. However, there is concern that export to Japan will decrease as coal demand in Indonesia increases. The trend of coal transport in Indonesia is a very important matter in ensuring the continued stable import of coal to Japan. Therefore, this paper proposes LFTS (Large-Scale Floating Transshipment Station for Loading Coal) to improve the coal transportation productivity. The LFTS is installed in the estuarine waters of the Markham River in Indonesia's East Kalimantan, and it is capable of loading, storing, and offloading coal. The partial mass distribution and local rigidity of the LFTS varies depending on the coal loading conditions. In addition, because the structure has a planar shape, the response of the LFTS shows elastic behavior. Design example of such a huge floating structure with the great difference of the displacement is unparalleled, it is very important to clarify a design fundamental subject. Therefore, in this paper, a preliminary LFTS design is provided, and it's characteristics in terms of stress and stability in static, and dynamic hydroelastic motion under various coal loading condition is investigated.

The color gamut of xvYCC is wider than that of film. We evaluated the color reproduction and developed a new method of converting the video signal, which reproduced color of a film in xvYCC color space faithfully.

An innumerable number of buildings in the coastal part of the east side of Japan were devastated by the Great East Japan Earthquake and Tsunami. Medical institutions also suffered the damage caused by tsunami, and the function to carry out the medical act has been spoiled. And the disabled concentrated on the medical institution which avoided tsunami damage. Under such circumstances, assistance from the water area began three days after the earthquake disaster, and much support supplies reached the stricken area. It was revealed that the support from the water area including the river was extremely effective against the stricken area. And then, the Tokyo Inland Earthquake disaster was assumed, floating medical support system (hereafter, Medi-Float) installed in the quay of Arakawa River in Tokyo was proposed. Medi-Float is movable; furthermore, it is built in the structural system of having very high isolation characteristics. The float proposed in this study is a facility based on a completely new concept and hence it is difficult to get approval as simply a hardware structure or facility, even if it is safe. Our study considers the constraints with respect to installing the system on the river as the basic plan of the specific Medi-Float. It takes into account the floor planning and flow planning based on operational methods, considers scale planning and weight calculation and the structural strength of the float foundation. The study conducts basic plan of the feasibility of the first-of-its-kind medical float as a marine structure. As the next step, the research on dynamic behavior of Medi-Float will be started, and the validity of this design is verified, technical issues in the design of the Medi-Float should be clarified.Copyright © 2015 by ASME

Wave energy convertors (WEC) of oscillating water column (OWC) types make compressed air due to vertical movement of a part of water column, which are surrounded by some walls in water. As a result, the compressed air works to rotate an air turbine which also works for an electrical generator. If a structural system can make to move water such like a water column, a shape of a structure would not matter. Wave dissipating caissons installed in or on the existing production line can make to transfer a water wave to a flow and to reduce wave energy by making to overflow them. The caissons which can be overflowed by the water would actuate a water region vertically such like an oscillating water column system. This study investigated if we can utilize wave dissipating caissons as a WEC. Wave dissipating caissons also decrease wave energy due to passing through themselves. Even so, when an air turbine can be installed onto the caisson in order to harvest wave energy, it would be possible to produce electricity at low cost. The study conducted model experiments using the model assumed that wave dissipating double-caissons were remodelled to OWC type WECs with side walls and evaluated performance of the primary conversion of them. In addition, effects of how to arrange the number of the WECs on the primary conversion efficiency were investigated with theoretical calculations based on the linear potential theory and the possibility of utilization of wave dissipating caissons as a WEC was examined in the study.

A plate structural system has great possibilities for construction of oceanic structures, especially, floating structures on the sea, which can be applied to a floating artificial base so as to construct floating airport, floating city, IT industrial base, etc.The purpose of this study is to propose an easy calculation method for natural frequency analysis of elastic plate as coupled vibration of plate and water. In the dynamic analysis of floating plate, most of research subjects were on wave response related until now, and papers focused on natural frequency analysis corresponding to response function are hardly found. In addition, experimental approaches by the model testing can't be found. The fluid analysis requires special knowledge with complicated procedure of calculation. It is known that added mass depends on frequency, and in case of vibration problem, it depends on both shape of vibration mode and frequency.Using nine testing models of plate existing on water, modal experiment was carried out as plate-water coupled vibration. The feature of added mass distribution were grasped by identifying natural frequency corresponding to vibration mode order, and through the study a practical estimation method of added mass which can be combined to structural mass, is presented. The validity of this method has been verified by the demonstration through comparisons.

The oceanic architectural buildings were designed in consideration of structural safety based on various structural calculations. However, there is not conclusive proof such as constructed buildings satisfy strength according to the expectation or the buildings built in 1970’s still satisfies specified concrete strength. Therefore, in this study, vibration characteristics of existing floating structure were measured by mode analysis. Generally mode analysis is performed by giving a measurement object a shock with the impulse hammer. But it is hard to be allowed to strike the existing oceanic architectural buildings with a big impulse hammer for a vibration experiment. Therefore, operational modal analysis (OMA) which does not give a shock to measurement object was adopted in this study. In the OMA, natural frequency, mode shape and damping ratio are calculated from the measurement results of ordinary vibration by ground vibration, winds and waves. OMA is used in a field of mechanical engineering. However, it is not easy to apply a vibration experiment by OMA to floating structure. It is because the mode peaks of rigid motions such as heaving and pitching motion in low frequency domain is prominent, and the mode peaks of elastic vibration are difficult to be confirmed. Firstly, we carried out a water tank experiment with floating elastic plate model. Concretely, elastic plate model in floating condition on the water was analyzed by OMA. Because mode peak of the elastic vibration in floating condition was detected by examining frequency response function carefully, it was confirmed that we could apply OMA to the vibration experiment of existing floating structure. Secondly, vibration characteristic of the floating lounge named “WATERLINE” in Tokyo Bay was investigated by OMA. Ordinary vibrations of the base and the building of “WATERLINE” were measured, and natural frequency, mode shape and damping ratio were calculated. And it was reported about vibration characteristic that is given by measurement of existing floating structure by OMA.Copyright © 2009 by ASME

A floating structure has many options for effective ocean space utilization, for instance, the well known floating airport project, called Mega-Float. But after the end of the project, small scale floating structure began to be paid to attention. As the good example of such a kind of floating structure, there is the floating restaurant named “WATERLINE” (Figure 1) in Tokyo Bay. “WATERLINE” is small scale floating structure, and it is moored at the Tennoz Canal that is the closed water area. Therefore, when the ship passes around the floating restaurant, ship wave forces give a great influence on dynamic behavior of floating restaurant. As for ship waves, several studies have been made on the wave resistance and influence on ship handling concerning ship waves, but it is hardly to find papers focused on influence that ship wave forces give to dynamic behavior of small scale floating structure. In this research, dynamic behavior of small scale floating structure by ship wave forces was studied through both theoretical and experimental approach. As for the theoretical analysis, the equations of the Boussinesq type to treat shallow water area were adopted, and ADI (Alternating Direction Implicit) method in a numerical calculation was used for the analysis of these equations. And the floating structure was assumed to be a rigid body, and the displacement responses by ship wave forces were analyzed. With regard to experimental study, dynamic behavior of “WATERLINE” and wave height by the ship wave were actually measured. This measurement data is a profitable basic data for other researchers and engineers in order to analyze a floating structure. In the present paper, the validity of the numerical calculation program for ship wave response analysis was verified by the comparison between calculation results and the measurement results, the characteristics of the displacement response and the wave height were discussed by the numerical results that had been obtained by changing by the ship’s speed and the distance between floating structure and the ship. In addition, the evaluation of habitability in vertical motion of the small scale floating structure at the canal was examined by the diagram proposed from our research results [1], [2]. And, in regard to the ship that passes over around floating structure, ship’s speed limit and minimum distance between the ship and the floating structure were proposed.Copyright © 2009 by ASME

This paper summarized the investigation results on the technological subjects in order to realize marine facilities constructed at the sea bottom, where human can live or work for a long period. It is important to grasp the needed technology for realization beforehand so as to expand the human activity field. The subjects to be solved obtained by evaluating the present construction technology was considered. From the results, the necessary functions and items to be researched and developed newly on the basis of scientific grounds, are reported. This technology must make it possible to built seabed natural resource development facility, seabed research facility and submarine city, etc. It can be said such a kind of building has many options and big possibility. Nowadays, necessity of research and development for the future rises needs are rising. Our own design of submarine hotel is shown using this study, and seismic response analysis was demonstrated. In consideration of Japan is earthquake country.Copyright © 2009 by ASME

Wave breaking forces acting on the nearshore structures, such as the underwater observation tower, are subject to breaking wave forces which leads to response behavior that is characteristically nonlinear. Most of the existing underwater observation towers in Japan were constructed in the wave breaking zone as this zone is abundant with underwater life and presents a fantastic under water scene. Convenient access to the observation tower is typically connected by a bridge connecting the tower to an onshore site. This study reported here presents the develop a structural analysis procedure for an underwater observation tower subject to the breaking wave forces using finite element analysis. The tower structure consists of vertical circular cylindrical form that may be tapered in some cases. A procedure for estimating the breaking wave forces and transferring the appropriate hydrodynamic pressure distribution to each nodal point in the finite element model is presented and discussed. The ratio between the total diffraction wave forces and total breaking wave forces was investigated, and then the breaking wave pressure distribution acting on the structural surface was studied. Using that ratio obtained through the comparative studies, the dynamic analysis was conducted in the various wave periods for a constant water depth. After summarizing these calculation results, an analytic method on underwater observation tower due to wave breaking forces was presented.

Since Japan is limited in area, the effective ocean space development is very important and urgent subject. Concerning a research and development of effective ocean space utilization, the MEGA-FLOAT was one of the most famous projects in Japan that had the purpose of a floating airport construction, and the numerous R & D were conducted aiming at actual construction and those results were reported in respect of conceptual design, construction method, fluid analysis, structural dynamic analysis, environment issue etc. However, the end was faced without achieving it, it can be said that the effect is large. After the end of that project, the realistic, small or medium size structure began to be paid to attention. As the good example of such a kind floating structure, floating pier and disaster prevention base having an advantage against an earthquake, floating restaurant etc. were constructed shown in Figure 1. In this paper, assuming the small size floating restaurant, the wave response analysis was studied, and the habitability of that structure was evaluated from the response calculation results. Concretely, the floating base part; barge type of the restaurant building was designed by the Class NK (Rules and Guidance for the survey and construction of steel ships, Part Q Steel barges). The calculation model consists of a three-story building and the base, that floating artificial base supporting the building was assumed by the elastic plate structural system, and also that building was of the frame structure system. In order to structural analysis, the restaurant model of two different structural systems was united into one body system. In this paper, it is called the hybrid structural system. Fluid effect was analyzed as the fluid-structural interaction problem. Concretely, the Boundary Integral Equation Method (BIEM) was used here, and the wave response calculation was demonstrated by that forces. The evaluation of habitability of the restaurant in vertical and horizontal motion was examined by the diagram proposed from our research results.

Dynamic response analysis of a floating artificial base-building due to wave forces was studied, which structural system was named as a hybrid structural system. It was assumed to be constructed by the combination of elastic plate and framed structure. The hybrid structure system enabled the matrix size to reduce in FEM analysis, and the improvement of the calculation efficiency was succeeded. The developed calculation tool made it possible to examine the dynamic characteristic of the building on the floating base under the various wave conditions. The natural frequency analysis and the structural response analysis were capable, besides the evaluation of habitability in relation with oscillation caused by wave motion became possible using the diagram of our result of the research.Copyright © 2006 by ASME

A structural design of the underwater observation tower constructed at wave breaking zone was studied in this research. Though the under water observation tower seems to be a rotational shell structure from its shape, actually, the rigid frame of beams and ribs exits inside wall, in which the frames are covered with curved plate element firmly against seawater pressure. Assuming that the observation tower was a pseudo-cylindrical shell, two results through our conducted research were applied for a practical structural analysis of the underwater observation tower. One is the unique and simple formula on added mass depending on elastic vibration, the other is transformation of total breaking wave forces into the wave pressure distribution over the surface of the observation tower. Using those results, the structural characteristic concerning displacement of the under water observation tower was examined through our own results.Copyright © 2006 by ASME

SiC (silicon carbide) lightweight mirrors are used for a large number of space telescopes, and SiC is also candidate as hopeful material for segmented mirrors of the next generation ground based telescopes from 30 to 100 m in diameter. However, an SiC mirror is difficult to shape because the material is very hard and brittle. We are developing an SiC mirror by means of the ELID (ELectrolytic In-process Dressing) grinding method, a grinding machine with rotary table of 800 mm in diameter and precision of 10 nm in control resolution, and computational simulations. The ELID grinding method is versatile for fabrications of very hard materials. In this study, we introduce test fabrications of SiC mirrors with 360 mm in diameter and equilateral triangle rib structures in the rear face. We developed a support tool with air actuator and oil pressure clamp for suppression of the mirror deformation for manufacturing of the thin mirror.

The floating structure of pontoon type is expected to be used for an artificial base. Assuming that its floating structure is constructed of plate structural system, we have studied on added mass yielded from elastic behavior of the plate. It is considered naturally that added mass is dependent on mode shape of vibration, for the analysis of the added mass, special knowledge of fluid dynamics is required. Therefore, a proposal of simple calculation method is significant. This paper aims to propose the simple equation for calculation of added mass. In order to develop it, we carried out modal experiment by floating elastic plate model. The distribution characteristic of added mass was grasped through that experiment. By applying those characteristics, the simple equation for calculation of added mass became successful in the proposal. The validity of the obtained simple equation was examined by comparison with present experimental results and other results.Copyright © 2003 by ASME

Large scale floating structures, such as floating airport and amusement park having two dimensional expanse in horizontal direction, which structural concept can be considered as plate-type structural system. This structural system has a great deal of potential to be applied to oceanic structures like a artificial ground. This practical fabrication will be done by a combination of units. The hydroelastic interaction problem and structural design have attracted the attention of researchers and structural engineers. This paper presents consideration and conclusion through the numerical calculation results of the natural frequency studied under the various supporting conditions by developed computer program. The theoretical development is obtained by a way of combination of finite element method (FEM) and boundary integral equation method (BIEM). As to natural frequency analysis of oceanic structures based on the fluid-structure interaction, in general, there is an assumption to make it possible by estimating properly the added mass of the structure surrounding by water. The added mass of floating plate obtained by BIEM is modified and transformed into mass matrix of plate in FEM analysis. Herein, FEM analysis is based on the bending vibration assumption.

We have developed a new display / video camera and wide-gamut characterizing tools for a new standard for extended-gamut YCC color space called xvYCC. Video systems adapting this standard will have improved accuracy of color reproduction of real world.