The current situation of network security and some measures for its improvement are presented. At first, some statistical data and profiles of network attacks are described with technical background, followed by some of basic counter measures for network attacks. The activities of Japanese government in the area are also mentioned briefly.

抄録全体を表示

Denials of Service (DoS) attacks are one of the most alarming threats on the Internet. A typical DoS attack disrupts the services of its target by usurping network bandwidth and overtaxing server resources to prevent legitimate access from getting through. Effective protection from DoS attack involves tackling the prevention, detection, traceback and mitigation at various levels. This article surveys DoS attacks commonly seen on the Internet, and a number of promising countermeasures against them.

抄録全体を表示

This paper describes “IPSec(IP Security) VPN system" and how it attains a theoretical maximum performance on Gigabit Ethernet. The Conventional System is implemented by software. However, the system has several bottlenecks which must be overcome to realize a theoretical maximum performance on Gigabit Ethernet. Thus, we newly propose IPSec VPN System with the FPGA(Field Programmable Gate Array) based hardware architecture, which transmits a packet by the pipe-lined flow processing and has 6 parallel structure of encryption and authentication engines. We show that our system attains the theoretical maximum performance in the short packet which is difficult to realize until now.

抄録全体を表示

In biometric authentication, the biometric data is registered and authentication is done by collation input biometric data with the registered biometric data. If the registered biometric data is stolen, there is a possibility that the the biometric data of registrants may be used improperly. It is very difficult to prevent such improper use because we no longer change biometric data. Therefore it is necessary to pay sufficient attention to the protection of biometric data. This paper proposes the application of one way function to biometric authentication in order to protect biometric data of registrants. We examine and discuss the possibility of application of one way function in biometric authentication.

抄録全体を表示

The VPN (Virtual Private Network) technique becomes more and more popular to protect contents of messages and to achieve secure communication from incidents, such as tapping. However, it grow in usage that a VPN server is used on a sub-network in part of an office-wide network. But, a PPTP system included in Windows operating systems cannot establish nested VPN links. Moreover encrypted communication by VPN hides a user of the VPN connection. Consequently, any administrators of network systems can’t find out the users of the VPN connection via firewall, moreover can’t decide whether if the user is legal or not. In order to solve this problem, we developed a multi step PPTP relay system on a firewall. This system solves all the problems of our previously developed PPTP relay system⁽¹⁾. The new relay system improves security by encrypting through the whole end-to-end communication and abolishing of prior registration of passwords for the next step. Furthermore, transport speed is accelerated, and the restriction of the number of steps on relay is also abolished. By these features the multi step PPTP relay system expands usability.

抄録全体を表示

This paper describes recent trends in three-dimensional shape measurement technologies and multi-spectral image capture and processing. Two types of rangefinder, triangulation method and time-of-flight method, have been developed in wide application fields, for example, generation of database of human body, archives of remains and ruins, security monitoring, etc.. Their response time and accuracy have been improved sufficiently for practical applications. Spectral imaging technique has attracted attention in the machine vision field to enhance measurement and inspection systems. This paper also describes color analysis techniques using an imaging spectrograph for acquiring multi spectral image in real-time.

抄録全体を表示

This thesis describes our new printing method of tone images by using "zigzag scanning" of electrostatically extracted ink jet which uses dielectric ink. The flight of the ink jet becomes a liquid thread from the nozzle, and ink turns into corpuscles at the other end of the liquid thread. At the printing process, we utilize in both liquid thread and corpuscles according to the gray levels of images. An ink flow was scanned right and left at the end of the nozzle (called zigzag scanning) according to the gray levels of images. The purpose of our research is the printing with having a high-quality in smoothed tone images but black and white. As for the zigzag scanning, resolution becomes 2 times bigger in an appearance without changing time and size of images recorded for to original picture image. In addition, the effect of decreasing a grainy touch on the image can be improved smoothly to a certain extent by utilizing such a tiny corpuscle in printing of high light area. In general, the scanning lines can be seen at the direction of sub-scanning according to the step width of the nozzle movement. Moreover, deterioration in the image quality might be occurred by the so called "moire pattern" of the image as an unwanted side effect, which is created under the mutual interruption between textures especially with the periodicity of the halftone dot image. The zigzag scanning contributes the smoothness of scanning lines, and maintains the periodicity of the halftone dot image as well, which reduces the degraded quality of moire and then enables an image quality rather natural through our human eyes.

抄録全体を表示

High-speed stacking two-dimensional bar-code detection systems under time-sharing light emission operation, which are highly useful in applications such as goods management on production lines and in automated warehouses, require a longer detection range to obtain highly reliable detection. A new stacking two- dimensional bar-code detection system is proposed in which a wide-angle detection lens is used to increase the amount of light incident on a photodiode after reflection from a barcode. Composite masked collimators are also employed to uniformly extend the depth of focus for three laser diodes. The best performance was obtained using composite masks with holes of 2.5 and 3 mm in diameter and a condensing lens with 40-mm aperture and 28.5-mm focal length. This system provides a long detection range of 14.2 cm for 0.25-mm 3-line barcodes, which is 1.38 times longer than that of conventional systems. This long range has potential application in high-speed, high-resolution barcode systems.

抄録全体を表示

In recent years, the traffic accident occurs frequently with explosion of traffic density. Therefore, we think that the safe and comfortable transportation system to defend the pedestrian who is the traffic weak is necessary. First, we detect and recognize the pedestrian (the crossing person) by the image processing. Next, we inform all the drivers of the right or left turn that the pedestrian exists by the sound and the image and so on. By prompting a driver to do safe driving in this way, the accident to the pedestrian can decrease.
In this paper, we are using a background subtraction method for the movement detection of the movement object. In the background subtraction method, the update method in the background was important, and as for the conventional way, the threshold values of the subtraction processing and background update were identical. That is, the mixing rate of the input image and the background image of the background update was a fixation value, and the fine tuning which corresponded to the environment change of the weather was difficult. Therefore, we propose the update method of the background image that the estimated mistake is difficult to be amplified. We experiment and examines in the comparison about five cases of sunshine, cloudy, evening, rain, sunlight change, except night. This technique can set separately the threshold values of the subtraction processing and background update processing which suited the environmental condition of the weather and so on. Therefore, the fine tuning becomes possible freely in the mixing rate of the input image and the background image of the background update. Because the setting of the parameter which suited an environmental condition becomes important to minimize mistaking percentage, we examine about the setting of a parameter.

抄録全体を表示

In this paper, we describe a new algorithm for tracking a known static target in image frames from a moving platform. We have noticed that a image point is environment sensitive, but those changes of grouped points energy have their own statistical similarities in two image frames within limited time interval. This approach analyzes correspondence of interest points around every feature points between inter-frames in image sequence in order to decide those feature points. We tackle these tasks with three broad approaches. First, we make an active contour model of a target in order to build some low-energy feature points. The feature points give constraints of the input state space for interest point detection in an input image frame. The second step is a method of detecting interest points around every kernel. We take into account auto-correlation method to indicate the presence of interest points for the purpose of features state space in consecutive image frames that can be tracked. The third step of our strategy is to detect the correspondence of interest points by a probabilistic relaxation method in tracking windows. The detecting process is iterative and begins with the detection of all potential correspondence pair in consecutive image. Each pair of corresponding points is then iteratively recomputed to get a globally optimum set of pairwise correspondences. Successful results are given for a real vide frames.

抄録全体を表示

This paper proposes a new method for image template matching that is based on the correlation between the edge-spins. The edge-spin is defined by the direction of the change of edge directions between neighboring pixels. When an edge direction rotates to the left from an objective pixel to its right neighboring pixel, the edge-spin has the value 1. When an edge direction rotates to the right, the edge-spin has the value 0. The edge-spin is a binary data that represents the rotation of the edge direction. The edge-spin is supposed to be robust to the change of brightness because the edge direction is not influenced by the liner change of brightness. The experimental results show that the proposed method has the superior reliability for the matching about most inferior experimental conditions in comparison with the conventional image template matching methods.

抄録全体を表示

This paper presents a method of continuous-time SAC (simple adaptive control) for MIMO (multi-input multi-output) nonlinear systems using neural networks. The control input is given by the sum of the output of the simple adaptive controller and the output of the neural network. The neural network is used to compensate the nonlinearity of plant dynamics that is not taken into consideration in the usual SAC. The role of the neural network is to construct a linearized model by minimizing the output error caused by nonlinearities in the control systems.

抄録全体を表示

Dynamic uniform temperature on thermal conduction surface is widely required in many applications. In our previous work, the Gradient Temperature Control (GTC) method for the uniform heating has been proposed, and the effectiveness of the control system was clarified. The main idea of GTC is to control the average and gradient temperatures on the surface in order to suppress the thermal interference of the heater. The temperature on the heating plate is made uniform not only in steady state but also in transient state. As a result, uniform thermal process and short process time until uniform heating are realized. In order to confirm the effectiveness of the GTC, experimental results for a realistic application are shown and evaluated.

抄録全体を表示

In this paper, we propose a pattern classification method of spectra of vibration data in a wrist by a motor-operated electric tool (MOET) using Self-Organizing Feature Map (SOM). We collect 27 data to evaluate the vibration patterns in a wrist for three kinds of MOETs. We compute spectrra of those vibration data and input them to a SOM network to find the spectral patterns. Based on the relations among vibration spectral patterns of MOETs under no load and load conditions, we show that the performance under load conditions can be evaluated by those of unloaded ones.

抄録全体を表示

Genetic Network Programming (GNP) extended from other evolutionary computations such as Genetic Algorithm (GA) and Genetic Programming (GP) has network structures as gene. Previously, the program size of conventional GNP was fixed and GNP programs have not introduced the concept of sub-routines, although GA and GP paid attention to sub-routines. In this paper, a new method where GNP with Automatically Generated Macro Nodes (GNP with AGMs) composed of a number of nodes is proposed for improving the performance of GNP. These AGMs also have network structures and are evolved like main GNP. In addition to that, AGMs have multiple inputs and outputs that have not been introduced in the past. In the simulations, comparisons between GNP program only and GNP with AGMs are carried out using the tile world. Simulation results shows that the proposed method brings better results compared with traditional GNP. And it is clarified from simulations that the node transition rules obtained by AGMs show the generalized rules able to deal with unknown environments.

抄録全体を表示

In this paper we propose a new searching method of Genetic Algorithm for Job-shop scheduling problem (JSP). The coding method that represent job number in order to decide a priority to arrange a job to Gannt Chart (called the ordinal representation with a priority) in JSP, an active schedule is created by using left shift. We define an active solution at first. It is solution which can create an active schedule without using left shift, and set of its defined an active solution space. Next, we propose an algorithm named Genetic Algorithm with active solution space search (GA-asol) which can create an active solution while solution is evaluated, in order to search the active solution space effectively. We applied it for some benchmark problems to compare with other method. The experimental results show good performance.

抄録全体を表示

This paper describes an extension of the flexible transfer system (FTS) with self-reconfigurability of the physical modular configuration. The FTS is a modular type of two-dimensional transfer system, and can take an arbitrary fixed configuration by manual deployment of modules. A decentralized control we previously proposed for the FTS can generate feasible transfer paths with the adaptability to environmental changes, but the fixed modular configuration causes the limited adaptability. This paper proposes a self-reconfigurable flexible transfer system (SRFTS) and the module reconfiguration method, and addresses the coevolution of the physical configuration and the control strategy. The SRFTS overcomes the drawback in the conventional FTS, and improves the transfer performance and the fault tolerance. The effectiveness of the SRFTS is illustrated by numerical simulations.

抄録全体を表示

A field experiment on transmission of eight 40-Gbit/s WDM channels is successfully carried out, where a 240-km optical transmission line is composed of four 60-km SMFs in an OPGW and three optical amplifiers. A few experimental studies on effective optical pulse waveforms for the transmission are made prior to the experiment. A carrier-suppressed RZ format is certified useful for increasing the dispersion compensation tolerance and the allowable optical input power to optical fibers. It is also found to be favorable against the polarization dispersion that pulse-width shortening by an EA modulator in front of the O/E converter. Applicability of the OPGW to 40-Gbit/s optical systems is clarified through error free transmission in all wavelengths.

抄録全体を表示

The function, which represents the outline such as circle, does not found by S-System and genetic programming system. The definition of the fitness in S-System is improved for resolving the problem. As the result, the function representing the outline is found by S-System.

抄録全体を表示

（誤）山形大学大学院理工学研究科
（正）山形大学大学院理工学研究科

抄録全体を表示