Recently IMO and IALA have developed the strategy of e-Navigation and the concepts of VTM to enhance the safety, efficiency and security of vessel traffic and protection of the marine environment. And current technical and functional trends require vessel traffic management systems to be improved so as to control vessel traffic not only in waters of harbour area, but also within EEZ waters. Under the consideration of these circumstances, a three-layered vessel traffic management system was proposed in this paper. The proposed system consists of three sub-systems, called Local VTS, Regional VTS and National VTS, and those sub-systems are designed respectively to be suitable for managing vessel traffic within their own jurisdiction waters.
It has been recognized that the risk from the vulnerability of GPS can lead to the extreme damage in the infrastructure of the civil and military in recent years. As an example, the intentional interference to GPS signal, named GPS jamming, was really performed to misguide GPS guided weapons during Iraq war in 2003, and the fact has also followed by the serious issues on GPS in civilian community. In the modernized military society, the navigation warfare(NAVWAR) based on the GPS jamming has been emerged and introduced as a military operation. The intentional interference to the future global navigation satellite system(GNSS) involving GPS must be also an important issue to civilian users in near future. This study is focused on the fundamental research prior to the research on "Potential principle of NAVWAR" under NAVWAR of the future warfare. In this paper, we would study on the investigation of NAVWAR based on electronic warfare(EW) and analyze characteristics of the jamming against GNSS's receivers. Then the general mechanism on GNSS jamming is proposed.
The studies on automatic ship collision avoidance system, which have been carried out in the last 10 years, are facing on new situation due to newly developed high technology such as computer and other information system. It was almost impossible to make it used in real navigation field 3-4 years ago because of the absence of any tool to give other ship's information, however recently developed technology suggests new possibility. This study is carried out to develop the automatic ship collision avoidance support system which considers ship's manoeuvrability into it's collision avoidance algorithm. One of the important part in ship collision avoidance system is collision decision module which can calculate collision risk with other ships and act properly to avoid the situation. Many of previous researches are using present ship's dynamic data such as present speed, position and course to calculate collision risk. However when a ship commences avoidance action, the real situation is quite different with one that has been estimated by the ship's initial data due to the ship's manoeuvring characteristic. Therefore it is better to take into account ship's manoeuvring characteristic from the stage of collision decision in ship collision avoidance system. In this study, these effects are included in the developed system. The proposed system are verified its usefulness in numerical simulation environments.
In this paper, the electromagnetic (EM) wave absorbers using TiO2 as a dielectric material with chlorinated polyethylene (CPE) were investigated in W-band radio frequencies. We compared the relative permittivity with reflectionless curve and the absorption properties of samples containing 40 wt.%, 50 wt.%, 60 wt.%, 70 wt.%, and 80 wt.% TiO2. It is possible to realize a complex relative permittivity satisfying the reflectionless condition by choosing composition ratio of TiO2. The optimized composition ratio of TiO2 for the maximum absorption property is about 70 wt.%. As a result, we have confirmed the realization of an EM wave absorber with a high absorption property in W-band radio frequencies.
Since fuzzy controllers are nonlinear, it is more difficult to set the controller gains and to analyse the stability compared to conventional PID controllers. This paper proposes a fuzzy PD+I controller for tracking control which uses a linear fuzzy inference(product-sum-gravity) method based on a conventional linear PID controller. In this scheme the fuzzy PD+I controller works similar to the control performance as the linear PD plus I(PD+I) controller. Thus it is possible to analyse and design an fuzzy PD+I controller for given systems based on a linear fuzzy PD controller. The scaling factors tuning scheme, another topic of fuzzy controller design procedure, is also introduced in order to fine performance of the fuzzy PD+I controller. The scaling factors are adjusted by a real-coded genetic algorithm(RCGA) in off-line. The simulation results show the effectiveness of the proposed fuzzy PD+I controller for tracking control problems by comparing with the conventional PID controllers.
The object of this study is to develop the method of safe conducting of a vessel through stormy sea when we encounter typoon or hurricane on ocean. The scope of investigation in this paper will be limited to safe maneuvering related only with rolling motions of a vessel. The processes of investigations are as follows; Firstly, we decide a CPA(Closest Point of Approach) with the center of the storm and decide significant wave height(H1/3) by SMB method and then calculate wave height of the highest of 1000 waves(H1/1000) and other data. Secondly, we make mathematical model of rolling motions of the vessel on the stormy sea and calculate the biggest rolling angle of the vessel and etc. Thirdly, we decide the most safe maneuvering method to ride out the stormy sea. By the above mentioned method we are able to calculate the status of the stormy sea and ships motions to be encountered and ride out safely through violently rough sea.
The aim of the paper is to solve the problem of customer reduction due to the difficulty of parts sourcing which impacts production delay and delivery delay in SC networks. Furthermore, this paper is to suggest the new inventory policy of MTS in order to solve the problem of current inventory policy. In order to compare two policies, a LCD maker is selected as a case study and the real data for 2007 years is used for simulation input. The maker uses MTO policy for parts sourcing which has the problem of lead time even if it has some advantage of inventory cost. Based on current process. The simulation program of AS-IS model and TO-BE model using ARENA 10 version is developed for evaluation. In a result, the order number of two policies shows that MTO is 52 and MTS is 53. However the quantity of order shows big difference such that MTO is 168,460 and MTS is 225,106. Particularly, the lead time of new inventory policy shows much shorter that that of MTO such that MTO 100 is days and MTS is 16 days. In spite of short lead time by MTS policy, new policy has to take burden of inventory cost per year. Total inventory cost per year by MTS policy is US 11,254 and each part inventory cost is that POL is US 1,807, LDI is US 2,166 and Panel is US 7,281. The implication of the research is that the company has to consider the cost and the service simultaneously in deciding the inventory policy. In the paper, even if the optimal point of deciding is put into tactical area, the ground of decision is suggested in order to improve the problem in SC networks.
In light of the growing traffic congestion problem and congestion cost, the container transport by railway has to be increased. The freight transport by railway can have decided advantages over trucks in terms of energy efficiency, emissions and cost for certain freight movements, just as transportation in the metropolitan region can have great advantages over driving truck. But the freight transport by truck should gain significant mobility benefits from a freight railway system. Thus, the DMT(Dual Mode Trailer) transport system which is coupled railway transport advantages with load transport advantages has been developed and used in the european countries. The DMT transport will therefore serve the areas required by transport organizers. The purpose of this paper is to estimate economical feasibility analysis for development of DMT transport system. Consequently, this study analyzed the characteristics of the DMT system. The horizontal load.unload system is being considered as an adoptable DMT system in consideration of the situation in Korea.
The management of safety at sea is based on a set of internationally accepted regulations and codes, governing or guiding the design and operation of ships. The regulations most directly concerned with human safety and protection of the environment are, in general, agreed internationally through the International Maritime Organization(IMO). IMO has continuously dealt with safety problems and, recognized that the human element is a key factor in both safety and pollution prevention issues(IMO, 2010). This paper proposes a human error analysis methodology which is based on the human error taxonomy and theories (SHELL model, GEMS model and etc.) that were discussed in the IMO guidelines for the investigation of human factors in marine casualties and incidents. In this paper, a cognitive process model, a human error analysis technique and a marine accident causal chains focused on human factors are discussed, and towing vessel collision accidents are analyzed as a case study in order to examine the applicability of the human error analysis technique to marine accidents. Also human errors related to those towing vessel collision accidents and their underlying factors are discussed in detail.