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Article type: Cover
2008 Volume 118 Pages
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Article type: Appendix
2008 Volume 118 Pages
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Article type: Appendix
2008 Volume 118 Pages
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Article type: Index
2008 Volume 118 Pages
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Article type: Index
2008 Volume 118 Pages
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Kenjiro HIKIDA, Tadatsugi OKAZAKI, Koji MURAI, Nobuo MITOMO
Article type: Article
2008 Volume 118 Pages
1-8
Published: March 25, 2008
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Usage of a ship handling simulator extends many topics such as crew trains, evaluation of nautical instrument and research of human factor etc. In any case, it is important to evaluate mental workload of mariners. In this paper, practical technique is introduced for presuming mariners' mental workload in bridge simulator by using data of mariners' nasal temperature which is measured by thermal image video camera. In addition, the results of this technique are compared with the results of subjective evaluation method which is NASA-TLX. As a result, some practical experiment derives effectiveness of this technique.
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Kinzo INOUE, Yuchang SEONG, Hiroko TAKAHASHI
Article type: Article
2008 Volume 118 Pages
9-14
Published: March 25, 2008
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A ship operator takes some actions of slowdown engine and altering course, when traffic becomes complicated and ship maneuvers under hard condition such as passing under a bridge. In such a navigation process, operational actions such as slowdown engine and altering course might be reduce difficulties on navigation or collision avoidance maneuver against other ship and obstacle. In this research, paying attention to operational load (maneuvering stress) given by these maneuvering actions of slowdown engine and altering course, it was examined whether the quantity of load was expressed by time delay as an index. And by conducting experiment of ship handling simulator, it was verified that how much difficulty of navigation has changed depending the time of delay, as compensation of action of slowdown engine and altering course.
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Xianghui XING, Kinzo INOUE, Hideo USUI, Wataru SERA
Article type: Article
2008 Volume 118 Pages
15-21
Published: March 25, 2008
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In recent years, navigation at nighttime is increasing inside ports and harbors by deregulation of restriction about entry port at nighttime. In order to ensure the safety of navigation in those areas, the evaluation based on the difficulty of ship handling at daytime and nighttime is needed. The Environmental Stress Model, as a model which evaluates quantitatively the difficulty of ship handling, is already verified that it's output coincides with mariner's physiology index. But the model is only for the situation of daytime. This research aims at developing the nighttime version of Environmental Stress Model, from the meaning, in the first paper, it was proposed that the quantitative expression model of mariner's perception of safety when approaching toward a shore at nighttime, based on the model of daytime. As the continue, in this paper, it was analyzed that the data about the perception of safety when encountering with other ship at daytime and nighttime, obtained through the questionnaires and ship handling simulator experiments. It was clarified that the difference in the mariner's perception of safety at daytime and nighttime, and the quantitative expression model of mariner's perception of safety at nighttime was proposed.
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Hiroko TAKAHASHI, Kinzo INOUE, Wataru SERA
Article type: Article
2008 Volume 118 Pages
23-29
Published: March 25, 2008
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Unsafe Ship-handling model (US-model) is known as an evaluation method, which analyzes the potential risk of marine accidents. In previous paper, this conventional model was improved for evaluating small obstacles such as the bridge pier. In this time, we aim to improve the conventional model to be able to evaluate the occurrence of unsafe situation for the collision risk against ships definitely. In ship-handling simulator, several traffic situations were set. From the experience's results, we cleared that following 2 points. - (1) In case of that one ship's size and crossing angle were changed, if the crossing angle was 135 degree and ship size became less than 80m, the gap of calculation's results between conventional model and improved model much occurred. - (2) In case of that all ship size were changed parametrically, if the ship size became less than 80m, the gap of calculation's results much occurred too. It shows it comes to application limit of conventional model, and to application area of improved model. In this experiment, this gap makes the precision difference of marine accidents ratio in 1.9×10^<-5>〜10^<-6>. But calculation time of improved model is very much than conventional one. So, it is necessary to decide an application of improved model by choosing a precision or calculation's time.
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Kimio TATSUMI, Takashi KUBOTA, Hidenobu FUJII, Nobuyoshi KOUGUCHI, Yas ...
Article type: Article
2008 Volume 118 Pages
31-37
Published: March 25, 2008
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Regulation should be modified properly according to an advancement of science and technology. However current science and technology allows a navigator to use more accurate ship's speed information, it seems that the regulation of a ship's speed was unmodified for a considerable time. Primary purpose of this research is to clear on some mismatching points between a present regulation and navigators' requirements on the basis of a ship's speed. At the first step of this research, the questionnaire and interview survey were carried out. This survey targets at the captain who maneuvers from 500 to 50,000 gross tonnages. The main subjects for question are how dose a captain use the current navigational instruments or SOME (Speed and Distance Measurement Equipment) such as Electric Magnetic Log, Doppler Sonar, and GPS, to collect ship's speed information and dose he feel satisfaction with an accuracy of ship's speed by means of above instruments. As the result of this survey, in Docking/Leaving maneuvering many captains obtained speed information from his visual sight and the navigational instruments, and need more speed over the ground than speed through the water. The desired demand accuracy of speed in Docking/Leaving maneuvering was about 1〜50 cm/sec, and the desired time was at once.
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Hitoi TAMARU, Masayoshi NUMANO, Shoichi HARA, Masanori Nakato
Article type: Article
2008 Volume 118 Pages
39-45
Published: March 25, 2008
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In maneuvering domestic cargo ships, most of the approach shiphandling for berthing is conducted solely by masters without the assistance of the crew, which can result in the increase of their workload and stress. Authors are developing a support system for approach. One of the functions is an automatic approach control function. First, an approach plan and a maneuvering model for actual ship experiment of trial ship "Shinei Maru" were made. The approach plan that is an aim of automatic control must be easy to understand by masters. The plan was made by actual approach data that "Shinei Maru" was approached to Shibaura Quay. To apply to many domestic cargo ships, a simple maneuvering model calculated by actual data was supposed. But the error of the simple model is large was expected. So in automatic approach control, an order rudder angle, an order CPP pitch angle and a ship's motion using the simple maneuvering model were calculated. An aim speed was adjusted by difference of an actual speed and the calculated speed. This effect was confirmed by actual ship experiment.
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Shintaro MIYOSHI, Yohsuke HARA, Kohei OHTSU
Article type: Article
2008 Volume 118 Pages
47-53
Published: March 25, 2008
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In the former report, we proposed a simplified new autopilot system with tracking function using a linearized-maneuvering model. And we demonstrated the actual sea tests of the proposed system. In this paper, we propose an extended new tracking system of the former simplified one. In this system, the ship's position is estimated by using Kalman Filter and using the estimated position, the cross track error from the desired track is estimated. The estimated cross track error are input into the ship's motion estimator and using the Kalman Filter technique, the optimal estimates of ship's maneuvering state variables composed of ship's lateral speed, yaw rate, yaw, cross track error and its changing rate are estimated. At last, the estimated maneuvering variables are input into the LQG controller calculation block and the optimal command of the rudder angle is calculated. In the report, we describe the theory of this tracking system, the result of simulation to determine the filter gain and the actual sea tests.
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Katsumori HATANAKA, Masaaki WADA, Masashi TODA
Article type: Article
2008 Volume 118 Pages
55-63
Published: March 25, 2008
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The low-cost sounding system measuring the shallow sea bottom topography for fishing industry has been presented in this study. The outline of the system is that the position data obtained by GPS and seawater depths measured by a fishing echo sounder on fishing vessels are accrued by the general sensor platform namely "Micro Cube" then those are stored into the database server to create a map of sea bottom topography. Since the accrued data include noises and burst errors due to the double reflections in water depths, the authors have examined the data analysis for removing suspicious water depths due to the double reflection from the bathymetric chart in our previous study. In this paper, the authors discuss other effective and general analytical method for erasing noises by a low-pass filtering based on the Discrete Wavelet Transform and statistics. The effectiveness of this investigation is examined using the experimental data carried out using 4 fishing vessels in Rumoi on the west coast of Hokkaido, Japan.
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Chia-Hung SHIH, Nobukazu WAKABAYASHI, Saburo YAMAMURA
Article type: Article
2008 Volume 118 Pages
65-72
Published: March 25, 2008
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Along with the appearance of distributed concept, traditional centralized management framework has been transferred to distributed management framework, especially in electronic commerce field. In the technical implementation level, because relational database technology is already very mature and easy to be implemented in distributed construction, so nowadays electronic business enterprises mostly use relational database management system (RDBMS) to store and manage their data. Although, in fleet management, because of ships cannot access to centric database through general internet construction when they are offshore, the data belong to ships themselves have the necessity of independent self-management. But RDBMS cannot completely satisfy this objective because it is not easy to be divided. In this paper, we propose to use Extensible Markup Language (XML) to construct ship data management model, so then it could be applied for fleet management and future port administration. The data model can be composed of many kinds of information, such as hardware (ship name, ship type, net tonnage, etc), software (schedule, service, passenger, etc) and freight (freight kind, freight charge, deliver country, etc). Multi-level data model can provide the ability for fleet inter-manageinent and communicating function to government related departments for port administration.
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Junji FUKUTO, Hayama IMAZU, Takanori MOCHIDA, Hiroaki FUKUI
Article type: Article
2008 Volume 118 Pages
73-81
Published: March 25, 2008
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A series of field tests for evaluating feasibility and effectiveness of an integrated information display system for collision avoidance support (INT-NAV: Integrated Navigational Information System on Seascape Image) was carried out with a training ship "Taisei Maru". The INT-NAV provides functions for organizing information from RADAR, ARPA, AIS and seascape video image, for enhancing situation awareness of OOW (Officer of the Watch), and for supporting decision making of collision avoidance. The first is the tests for experienced OOWs to investigate how the INT-NAV is used and to get subjective evaluation of the INT-NAV based on the actual use of it. The second is the tests for novice mariners to get subjective evaluation based on experience of the INT-NAV expressed on a small simulator. The INT-NAV rated better than conventional way of displaying information in almost every item for the evaluation.
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Mingyang Pan, Masaaki Inaishi, Xiaoyu Zhao, Akira Kawaguchi
Article type: Article
2008 Volume 118 Pages
83-89
Published: March 25, 2008
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The cost of computation becomes a bottleneck for an agent based marine traffic simulation. This is especially true when investigating interferences of a large number of ships and static objects placed in the sea. In general, a collection of ship agents built with a simple sensing model mandates a quadratic time complexity of O (n^2) for sensing each other. The runtime cost required for sensing the environment sharply increases and the system performance rapidly deteriorates, as the number of environment elements increases. This paper presents a grid based sensing model, a new approach for building an autonomous ship agent. The aim of this research is to address the issue of time and space complexities. The proposed model reduces the cost of time and space for running the marine traffic simulation system implemented with the previous work of a ship cluster behavior model. Analysis of the grid based sensing model and its overall effects based on simulation experiments are discussed.
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Akira MIYAZAWA, Takahiko FUJISAKA, Hayama IMAZU
Article type: Article
2008 Volume 118 Pages
91-98
Published: March 25, 2008
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In this paper, the placement of radars is studied to identify vessels which cruise Tokyo Bay using ISAR (Inverse Synthetic Aperture Radar) images. First, the positions and motion data, for example, course, speed, rolling, pitching and yawing, of the training ship "SHIOJIMARU" were acquired. The observed ISAR images were generated in the computer simulation using the motion data of "SHIOJIMARU", in the case of several different radar places in Tokyo Bay. As a result of inquiring the simulated ISAR images, when having placed the radar to two places, Tsurugi Saki and Kannon Saki, it was possible to identify vessels using ISAR images.
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Kyoko TAKASHIMA, Toshiyuki KANO, Mitsuru KOBAYASHI
Article type: Article
2008 Volume 118 Pages
99-106
Published: March 25, 2008
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Ships have an advantage of economical and ecological transportation, but they are strongly affected by marine environments such as winds, waves, currents, and it is difficult for them to keep the operation schedule. Actually, coastal ships have been operated with considerably high engine power to avoid the delay of arrival, and often have to wait for a long time outside the destination port. If this waiting time outside the destination port can be used for the passage time, the engine power during the voyage can be largely reduced, which leads to a large amount of fuel saving and reduction of CO_2 emission. In this study, based on the precise environmental forecast and the ship's speed and engine performance in waves, the authors have developed two methods to minimize the fuel during the voyage with keeping operation schedule. Backward Dynamic Programming and Forward Dynamic Programming were used to calculate the minimum fuel route. A coastal Ro/Ro ship plying between Tokyo and Tomakomai/Kushiro in Hokkaido was used as a model ship in this study. Comparing the fuel consumption on the minimum fuel route calculated by these two methods with that on the actual route by simulations, the effectiveness of the proposed methods for energy saving operation was investigated.
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Yasuo YOSHIMURA, Hideo YABUKI, Yasunori YOKOO, Toshihiko KAWASHIMA
Article type: Article
2008 Volume 118 Pages
107-113
Published: March 25, 2008
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In 2005, small fishing boat "Shinsei-maru No.3" was discovered at the off Cape Nosappu under the capsized condition, without being rescued until that time. From this accident, seven crew were lost. According to the official report of the Marine Accident Inquiry Agency, the fishing boat was returning to her home port Hanasaki, and met the container ship that was cruising from North America to Pusan and Hong-Kong. The collision was caused as the followings. The fishing boat was under crossing condition in front of the container ship from the left side of the container ship, but did not alter the course. Meanwhile, the container ship did not sound the warning signal to the fishing boat. Then, the fishing boat collided at the port-side bow of the container ship, and then capsized. In this paper, the physical mechanism that caused the capsizing of the fishing boat is investigated based upon the experimental model tests and manoeuvring simulations. Also, the investigation about the ship handling of the container ship is done for the prevention of such capsizing.
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Shinsuke URUSHIDANI, Yuji SANO, Toshiki KIKUCHI, Junichi ABO
Article type: Article
2008 Volume 118 Pages
115-121
Published: March 25, 2008
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The proportion of dozing in all ship accidents is about 7% (2006). The purpose of this study was to investigate ship accidents caused by dozing watch-keepers. Marine accidents that had been described to the judgment record of the Marine Accidents Inquiry Agency between 1994 and 2003 were used for analysis. The authors investigated the relationship between the situations at the doze shipwreck by analyzing data that included a 30-item categorization procedure, and performing a Cluster Analysis. Analysis also included categorization of accidents according to the type of vessel and vessel use (i.e., fishing vessels; cargo ships). In both types of vessels there was a notable relationship between the situation of "The passage of time from the departure port is long" and the influence of "Work tiredness". The analysis of fishing vessels revealed there was a notable relationship between the situation of "The passage of time from the departure port is long" and the influence of both "Awake rhythm" and "Work tiredness". The analysis of cargo ships revealed there was a notable relationship between the situation of "The passage of time from the departure port is long" and the influence of "No stimulation". These results suggest that consideration of vessel type and use may be necessary in developing counter measures against dozing accidents that result from long-duration navigations.
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Haruo MIMURA, Shuhei OKUYAMA, Hiroshi ISHIDA
Article type: Article
2008 Volume 118 Pages
123-133
Published: March 25, 2008
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Changes in colony-forming eutrophic marine bacterial populations in a ship's ballast water and sediment were examined for 7 voyages in 2005 to 2006. In the ballast water taken in Japan, total numbers of colony-forming cells were highly variable in the range of 10^<3.1> to 10^<5.6> colony-forming units (CPU) ml^<-1> regardless of the season. The ballast water loaded in Japan was exchanged in the high seas in the Indian Ocean. During the exchange of ballast water, the values in the samples taken from discharging and reloading ballast water varied from 10^<3.2> to 10^<4.7> CPU ml^<-1> and 10^<2.7> to 10^<5.2> CPU ml^<-1>, respectively. When the reloaded ballast water was discharged at the Ras Laffan port in Qatar, the values varied from 10^<2.6> to 10^<5.1> CPU ml^<-1>. These results indicate that the ballast water exchange in the high seas is not effective as for the reduction of marine bacterial populations in ballast water. In the samples of sediment, the values between 10^<5.2> and 10^<7.2> CPU ml^<-1> were estimated for all seasons in which voyages took place, indicating the importance of management of sediment in ballast tanks as well as ballast water of ocean going vessels. As for the numbers of Vibrio sp. cells, which made colonies on the selective agar plate at 20℃, in the ballast water and sediment samples, the values varied from zero to 10^<5.4> CPU ml^<-1>, and so far examined, we did not detect pathogenic Vibrio cholerae, which can grow even at 37℃, throughout all the seven voyages.
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Yoshiji YANO, Nobukazu WAKABAYASHI
Article type: Article
2008 Volume 118 Pages
135-143
Published: March 25, 2008
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The situation of the bottom fouling of a ship is not the same in an individual ship according to lapsed days after dry docking, the condition of ship services and mooring environment etc. And the quantification of the degree of bottom fouling are assumed to be difficult. The degree of the bottom fouling are often judged from an indirect viewpoint such as decrease of ship speed, increase of main engine output and fuel consumption. To presume an increase of the friction drag because of the bottom fouling, the short stopping experiments are designed and have been executed by Training Ship Fukae-maru, the graduate school of maritime sciences, Kobe University. It is possible to experiment in a short time of about 30 minutes and wide sea room is not needed to execution in case of Fukae-maru. The authors propose this experimental maneuver. Then the methods of analysis and the result of analysis at present stage are described.
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Hiroaki SETA, Takashi TOMIYAMA, Yoshiyuki SAKAI, Masamitsu ITO
Article type: Article
2008 Volume 118 Pages
145-150
Published: March 25, 2008
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It was common that wooden oars used for a cutter would break and the broken oars would be on the scrap. This study attempts to reuse the broken oars and develop the oars which are useful as wooden oars. The fundamental way is to make one rebuilt oar by reusing two broken oars. It is necessary to abide the standards of the length and diameter of oars, and it is also necessary to consider the characteristics such as the durability and water resistance. Therefore, the rebuilt oars were united with the scarf patch, and the united part was bonded with an epoxy resin. Besides, the oar was reinforced with glass sheet at its uniting location. In order to investigate the characteristics of the rebuilt oar, the measurement of the amount of flexure and the pulling test were carried out. These results showed that rebuilt oars performed as well as ready-made wooden oars.
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Shigeki SAKAKIBARA, Michito KANEKO, Yoshiji YANO
Article type: Article
2008 Volume 118 Pages
151-158
Published: March 25, 2008
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Recently, shipyards in the world have been fully operated due to large demand of the maritime transportation, especially bulk cargo ship and energy cargo ships such as crude oil, LNG and LPG carriers. In a shipyard, some trouble has been occurred, which is a marking on ship hull by wearing of the outer rubber of pneumatic fenders. In this paper, a marking-less pneumatic fender has been developed by investigation on new materials of the outer rubber using effect of lubrication, and by field tests for the prototype fenders applying the new outer rubber on them. In this investigation we also developed a new wearing test apparatus for the wearing between the rubber fender and the ship-hull.
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Shigeki SAKAKIBARA, Masayoshi KUBO, Eiichi KOBAYASHI, Yuichiro OTAKE, ...
Article type: Article
2008 Volume 118 Pages
159-168
Published: March 25, 2008
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Recently, it has been announced as a warning that the Tokai, Nankai and Tounankai earthquakes will be anticipated to surely occur within next 30 years. These earthquakes involve large scaled tsunami. When the tsunami attacks ships moored inside harbor basin, the motions might attain large movements that exceed the safe mooring conditions due to the surface elevation, the currents and a resonance effect with natural periods of sway or surge of the moored ships based on our previous study which proposed a numerical simulation procedure of moored ship motions induced by tsunami. In this paper using the simulation method, we investigate characteristics of the moored ship motions and the mooring loads, affected by berth location, ship kind, ship condition, and mooring system.
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Nobuyuki FUJITOMI, Shigeaki SHIOTANI
Article type: Article
2008 Volume 118 Pages
169-175
Published: March 25, 2008
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A simplified estimation of the height and period of waves generated by a small vessel was proposed in previous papers. Estimated Heights and periods of waves were in good agreement with field results using a small vessel. In this paper, the new method called MUSIC (Multiple Signal Classification) was proposed for analyzing the direction of ship waves. The distribution of directional spectrum of ship waves estimated by MUSIC presented the sharper monotone peak, and the estimated result were supported by field results using a small vessel. The proposed estimation of ship waves by MUSIC was confirmed to be very effective.
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Toshio ISEKI
Article type: Article
2008 Volume 118 Pages
177-183
Published: March 25, 2008
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The non-linear ship responses, such as parametric rolling and pure loss of stability, have become the key issues in the research field of ship stability. In order to investigate these non-linear phenomena, it is well known that the higher order spectral analysis should be introduced and the non-linearity must be treated properly. In this paper, the instantaneous bispectral analysis, which is an application of the time-varying coefficient auto-regressive (TVAR) modeling to the higher order spectral analysis, is proposed to investigate the non-linear and non-stationary ship responses with focusing on the skewness of the data. First of all, the non-linear pitching motion and the fluctuating skewness, which were reported in the previous paper, are investigated and simulated using simplified equations of motion for the one-degree of freedom. Secondly, the instantaneous bispectrum is defined as an extension of the instantaneous power spectrum that is based on the TVAR model. The time history data that were obtained during on-board tests are investigated by the instantaneous bispectral analysis, and the phase angle of a peak is followed in the time domain to explain the fluctuating skewness. The effectiveness of the instantaneous bispectra is shown for analyzing the transition of skewness of non-linear ship responses.
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Yasuto SUMIYA, Akira ISHIDE
Article type: Article
2008 Volume 118 Pages
185-193
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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Satellite-based Automatic Dependent Surveillance (ADS) using a polling protocol can reduce a transmission delay greatly compared with the conventional ADS using the satellite data communication that meets ICAO Aeronautical Mobile Satellite Services (AMSS) standards. Although the polling protocol shows excellent performances, it still has some shortcomings. In the polling ADS, an ADS report request must be transmitted for every ADS report transmission, and the guard time between successive ADS reports must be larger than the maximum difference of round-trip times between a satellite and an Aircraft Earth Station (AES). These cause some deterioration in transmission efficiency of the channels. This report describes self-synchronized ADS using a satellite. It improves the transmission efficiency over the channels of both ADS report request and ADS report transmissions. Since any modulation and coding schemes can be used with this protocol, it can also be applied to future aeronautical satellite communication systems.
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Masato FUJITA
Article type: Article
2008 Volume 118 Pages
195-201
Published: March 25, 2008
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Automatic Dependent Surveillance (ADS) equipped aircraft transmits its position, the predicted position at the time of 37 minutes later once every 1600 seconds, the location of next waypoint and the estimated time of arrival at the waypoint, etc. The ground system uses this information for surveillance. The update rate of the position information is much lower than that in radar surveillance (4 sec - 10 sec). Therefore, the position prediction plays a key role in ADS. This paper gives the definition of 'longitudinal speed prediction error' and gives the distribution of them using ODP (Oceanic Air Traffic Control Data Processing System)'s position prediction algorithm. It also gives an example of a large speed prediction error and gives the distribution of longitudinal speed prediction errors, if such errors were remedied.
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Shunichiro KONDO, Takuji EBINUMA, Akio YASUDA
Article type: Article
2008 Volume 118 Pages
203-211
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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Ionospheric scintillation induces a rapid change in the amplitude and phase of radio wave signals. This is due to irregularities of electron density in the F-region of the ionosphere. It reduces the accuracy of both pseudorange and carrier phase measurements in GPS/Satellite Based Augmentation System (SBAS) receivers and can cause loss of lock on the satellite signal. Scintillation is not strong at mid-latitude regions, but severe effects occur mainly in a band approximately 15-degree latitude on either side of the magnetic equator and sometimes in the polar and auroral regions. Most scintillation occurs for a few hours after sunset during the peak years of the solar cycle. In Japan, several ionospheric scintillations were observed by Electronic Navigation Research Institute (ENRI). This work intended to investigate the scintillation characteristics in Japan and statistically evaluate constant bandwidth phase locked loop (PLL) and a Fast Adaptive Bandwidth (FAB) PLL performance under the ionospheric scintillation condition. The results show that the characteristics are consistent with the models proposed in early studies and the FAB PLL has the flexibility against the scintillation effects compared with the constant PLL.
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Takuji EBINUMA, Shunichiro KONDO, Chou GAN, Akio YASUDA
Article type: Article
2008 Volume 118 Pages
213-220
Published: March 25, 2008
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Galileo is the European Global Navigation Satellite System (GNSS) designed to be interoperable with the United States' Global Positioning System (GPS). Galileo and GPS interoperability means that hybrid GPS/Galileo receivers will offer improved performance in several ways compared to GPS- or Galileo-only receivers. This paper presents the design and implementation of a software GPS/Galileo receiver, together with testing results using a real Galileo signal from GIOVE-A, the first Galileo in-orbit validation satellite. Furthermore, a new navigation solution algorithm to estimate the GPS-Galileo system time difference is proposed. Hybrid navigation results show that 2 m (2drms) positioning accuracy can be achievable without knowing the exact system time difference.
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Kazuhiko TSUCHIMOTO, Nobuaki KUBO, Takuji EBINUMA, Akio YASUDA
Article type: Article
2008 Volume 118 Pages
221-227
Published: March 25, 2008
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Multipath is one of the major error sources in Global Positioning System (GPS) measurements. Separation from reflection surfaces is the most effective way to reduce the multipath errors, but it is not always possible. Currently, many multipath mitigation algorithms which modify tracking loop discriminators have been invented to reduce the effect due to the multipath signals arriving after the corresponding line-of-sight signal. These techniques, however, are not applicable when multipath signals are stronger than the direct signal. This paper proposes a new multipath mitigation technique under such conditions. Instead of finding the point to maximize the correlation power using any code discriminator, the proposed algorithm detects the rising edge of the correlation triangle of the line-of-sight signal which always arrives earlier than the multipath signals. In order to evaluate this new technique, a Signal Quality Monitoring (SQM) receiver was used to collect correlation curves during code tracking. The post-processing results showed that the positioning errors caused by stronger multipath signals were effectively removed by the proposed mitigation algorithm.
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Hideki Yamada, Tomoji Takasu, Nobuaki Kubo, Takuji Ebinuma
Article type: Article
2008 Volume 118 Pages
229-235
Published: March 25, 2008
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The purpose of this paper is to evaluate the stand-alone positioning accuracy and the satellite visibility when combining the GLONASS to GPS systems. Station and car navigation results showed that the satellite visibility was improved by the additional GLONASS satellites in limited sky view areas surrounded by tall buildings, but the stand-alone positioning accuracy of the combined GLONASS and GPS systems was worse than that with only GPS. The GLONASS ephemeris error was considered to be one of the main error sources to degrade the stand-alone GLONASS/GPS positioning accuracy. In order to evaluate the effect of GLONASS ephemeris accuracy, the transition of GLONASS ephemeris errors for the past three years was analyzed. The results showed that the GLONASS ephemeris errors had been improved by 0.3m for legacy GLONASS satellites and 1.7m for newer GLONASS-M satellites. However these errors are still about five times as large as GPS ephemeris errors.
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Jingci XIE, Masayoshi KUBO
Article type: Article
2008 Volume 118 Pages
237-243
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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Wheat and rice are staples for much of the world's population. Wheat is grown worldwide; however, 90% of rice production and supply is in Asia. In the case of wheat, share of trade occupied to production is more than 20%, and that of rice is only 5%. Especially in Africa, Starvation frequently happens in many countries. The import of wheat and rice is increasing over the last 20 years. Here, a comparative study is undertaken on maritime trade of wheat and rice destined for Africa. For comparison, firstly, the feature of production and supply becomes clear. Secondly, trade feature is also discussed. Moreover, we show that agricultural policies significantly affect the transportation of wheat to Africa. On the other hand, we show that the export of rice to Africa is a regular trend. At last, based on the comparison of trade, we predict the number of maritime bulk carriers of wheat and rice for Africa. We believe that this research is extremely useful to maritime transportation to Africa.
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Yoshio NISHINO, Masayoshi KUBO
Article type: Article
2008 Volume 118 Pages
245-252
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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We confirmed the similarity between model bag and prototype bag which are planning to use for fluid transportation by vessel. It is difficult to apply the similarity lows for membrane material. Therefore, we carried out several size model experiments with same membrane material. In these experiments, deformation, tension, strain and pressure of membrane has been shown. According to the experimental results, static tension and strain on membrane of model bag were same as those of prototype bag, and static similarity low was cleared. And, experimental results can be clarified using the numerical model developed in this paper.
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Mikihiko SATO, Yukiomi NAKAGAWA
Article type: Article
2008 Volume 118 Pages
253-258
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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Paper materials have become a wide use for inner packages of industrial products because of their environmentally friendly sources. Such paper packages, however, produce paper dust by the abrasive wear during transportation, which may, in turn, damage the packed product. In this paper, abrasion wear tests of a linerboard were performed with a vibrational apparatus and an abrasive steel tool, and the amount of paper dust thus produced was measured under various conditions. It was found that, assuming a constant friction between the test paper and abrasive steel, the wear rate is almost proportional to the work done by the tool, independent of the test condition. This new finding indicates that the kinetic friction and the load dependence of the paper dust produced can be taken as a measure to investigate the abrasive wear of paper packages.
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Mitsuko NISHIGUCHI, Saburo TSURUTA, Hisayuki KUROKAWA, Tomikazu KAZAMA
Article type: Article
2008 Volume 118 Pages
259-270
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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This paper shows the definition and the usefulness of "Core Technicians" for realizing prompt restoration of port logistics from earthquake disaster. In order to clarify the technicians for restoring from the earthquake disaster, inquiries were made to collect qualifications and licenses of the technicians along with their residential locations. Applying Quantification Type III and Cluster Analysis, four types of Core Technicians were identified, corresponding to four levels of the initial restoration work. They are named as "Super Core", "Longshoring Core", "Stevedoring Core", and "Container Core". Introduction of these Core Technicians is useful not only for increasing the number of secured technicians after the earthquake disaster but also useful for developing framework to estimate the number of cargo handling technicians for transporting emergency goods.
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Nguyen Thanh Thuy, Etsuko Nishimura, Akio Imai
Article type: Article
2008 Volume 118 Pages
271-281
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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Faster turnaround time of vessels is one of paramount factors in a container terminal for assuring competitive advantage in the shipping industry, which can be achieved by efficient handling process of vessels, especially the associated loading plan in the loading sequence. This paper deals with the ship loading problem regarding to the number of cranes to be used in a loading process while keeping reasonable ship stability. In order to preserve the ship stability, some heavier containers may be stowed at the bottom of ship holds. When those containers are stacked below others on a yard container block which are withdrawn later, it may required a number of rehandles when they are retrieved from the blocks. The efficient of loading process is evaluated by the minimum number of container rehandles required. To solve this problem, a mix integer programming is formulated. The genetic algorithm, which is widely applied for a plenty of practical mathematical programming, is employed as a heuristic for the nearly optimized solutions and a wide variety of numerical experiments was made where solutions by this problem are useful and applicable in practice.
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Van Thuan PHAM, Hiroaki KOBAYASHI
Article type: Article
2008 Volume 118 Pages
283-289
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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If the ship handling ability can be evaluated, the safety of navigation would be assured. Generally, the handling ability has not been defined yet. In this paper, the handling ability is called as the handlability. In order to define the ship handlability, we have been developing a standard evaluation method by the basic of difficult situation. The difficult situation is the approaching jetty. The handlability includes both of ship maneuverability and human characteristics. Numerical simulations are carried out to estimate the ship maneuverability. By comparing between numerical simulations results and mariner handling results, we evaluate the ship maneuvering characteristics under control of human. These evaluations enable us to define standard criteria on the handlability. In this paper, the study of a container vessel is introduced.
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Nam-Ninh HA, Hiroaki KOBAYASHI
Article type: Article
2008 Volume 118 Pages
291-297
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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In the paper "Use of Simulator in Assessment, Learning and Teaching of Mariners", the "safe navigation" is recognized as the balance between the mariner's competency and "navigation environmental difficulty". The "nine elemental technique for safe navigation" was developed for assessing the mariners' competency. The "technique of positioning" is defined as "the technique to find the position of own ship by selecting and recognizing proper objects by visual observation, radar, etc to understand her position and motion". At the present time, it is difficult to assess the concrete level of "navigation environmental difficulty". However, it is estimated that the behaviors of experienced mariners in bridge team indicate the required level of behavior to deal with "navigational environment". And analyzing experienced mariners' behavior could be estimated to bring us the required level with concrete values. Therefore, firstly in my research, that analysis on the "technique of positioning" was carried out. From this viewpoint, we have dealt with the behavior level shown by experienced navigators as the required level. The following chapters express the analysis of the relation between the navigation environmental difficulty and one of the most important techniques - "technique of positioning".
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Tomohisa NISHIMURA, Hiroaki KOBAYASHI
Article type: Article
2008 Volume 118 Pages
299-305
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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In order to make a rational countermeasure against maritime collisions, seafarers' characteristics on lookout in collision avoidance have been investigated. The function of the lookout is categorized into four factors, which are Detection, Recognition, Prediction and Planning of avoidance. The characteristics of the detection are discussed in this study. The detection means detecting presence of vessels. Lookout range and detection range are applied to indexes in order to study the characteristics. The followings are verified. High traffic density or restricted visibility makes mariners use a short radar range therefore the range of detected vessels is close to their own vessel. The detection range can be expressed by an exponential function of the Napier's constant which makes the traffic density to be as a parameter. The detection range is 63±17% of used radar range.
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Serdar KUM, Masao FURUSHO, Masaki FUCHI
Article type: Article
2008 Volume 118 Pages
307-314
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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The objective of this paper is to determine the level of Vessel Traffic Services Operators' (VTS-Os') Mental Workload (MWL) by using NASA Task Load Index (NASA-TLX). For this purpose the questionnaire is prepared and submitted to the Turkish VTS Operators (in the Istanbul and Canakkale VTS Centres) who has a long term sea experience as a Ship Master and submitted to the Japanese VTS-Os in the different locations (Akashi Strait, Bissan Seto, Kurushima and Kanmon Straits). The VTS-Os' MWL is subjectively determined by using NASA-TLX because of its origin that includes the operators judgements. In the analysing part, MWL of the Turkish and Japanese Operators are compared and also the relationship among the different safety culture of VTS-Os and their characteristics are investigated. The results show that there is not any significantly difference between Turkish and Japanese Operators' MWL, and the MWL is independent from operators' profile variables such as; age, marital situation, sea experience, experience at VTS Centre and educational level.
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Article type: Appendix
2008 Volume 118 Pages
App3-
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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Article type: Appendix
2008 Volume 118 Pages
App4-
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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Article type: Appendix
2008 Volume 118 Pages
App5-
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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Article type: Appendix
2008 Volume 118 Pages
App6-
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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Article type: Cover
2008 Volume 118 Pages
Cover2-
Published: March 25, 2008
Released on J-STAGE: January 15, 2017
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