• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.120-131
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• 2004

In this paper, we propose the method of a motion planning generation in which the movement of the 3-link leg subsystem is constrained to a slider-link and a singular posture can be easily avoided. The proposed method is the jumping control moving in vertical direction which mimics a cat's behavior. That is, it is jumping toward wall and kicking it to get a higher-place. Considering the movement from the point of constraint mechanical system, the robotic system which realizes the motion changes its configuration according to the position and it has several phases such as; ⅰ) an one-leg phase, ⅱ) in an air-phase. In other words, the system is under nonholonomic constraint due to the reservation of its momentum. Especially, in an air-phase, we will use a control method using state transformation and linearization in order to control the landing posture. Also, an iterative learning control algorithm is applied in order to improve the robustness of the control. The simulation results for jumping control will illustrate the effectiveness of the proposed control method.

• Journal of the Korea Society of Computer and Information
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• v.7 no.2
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• pp.46-52
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• 2002

Trend of wire internet has been transferred to wireless internet gradually due to the spread of mobile phone which made Possible Mobility and portability which wire internet could not afford. Not only front line of business part can access business information but also people can use government information for their daily life without limit of place. The frequent report of larceny and misuse of information has been issued to social sector that the need for IDS considering wire wireless internet. In this paper to design IDS to protect information first, searched wire internet intrusion type, intrusion detection method, and wireless intrusion type. In this paper, first, separate abnormal access at the point of system landing and detect intrusion attack with disguise through mobile wireless internet. Due to the intruder can access system normally with disguise, Circuit Patrol model has been suggested to monitor from intrusion attack.

• The Journal of Fisheries Business Administration
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• v.36 no.1 s.67
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• pp.121-138
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• 2005

This study was conducted to investigate the economic effect of the release of seed flounder to the central area of the West Sea, which was analyzed into both direct and indirect effects. The results showed that based on the data collected from partial area, the economic effect of flounder seed release reached 6.97 times, average catch proportion was 32.27$\%$, and recapture rate was 11.26$\%$, suggesting that economic effect was very high. In addition, it was observed that the recapture rate was greatly higher than 2.05$\%$, that of Break-Even-Point. It was noted that the increased catch by the release of seed flounder resulted in the increase in commission of sales and the increase in sports fishing. Another economic effect observed were diverse including the increase in income of fishing village, elevated spirit to proper management of fisheries resources, maintaining of willingness to live in fishing village through activation of local fishing village, prevention of illegal fishing including capture of juvenile fish, and the increase in the supply of sea food of high quality. It is emphasized that although the investigation was conducted in the same area, the results will vary by size at release, time at release and other factors. Finally, there is a need to expand species and area of study for more active economic analysis incorporating natural sciences.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.3
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• pp.261-271
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• 2006

The present study is aimed at evaluating the economic effectiveness of Abalone, haliotis discus hanai Releasing Project(ARP) conducted in the fishing ground owned by a fishing village in Ulsan, Korea. The results were summarized as follows: First, an average ratio of released abalones in the total landing after releasing is shown to be 85.0%. Second, the recapture rate of released abalones is 46.8%, exceeding the recapture rate of BEP(Break-Even-Point), 22.9%. Third, it is evaluated that total economic effectiveness of the ARP is 6.7-6.8 times, net effectiveness is 2.2-2.3 times, and the NPV(Net Present Value) discounted by a 8% interest rate is 474, 635 thousand wons, indicating the project is profitable. Considerable parts of the positive results on the ARP are based on some beneficial conditions, including the selection of favorable releasing sites, best self-regulation system of a fishing village for preservation of seaweed facilities and continued activities for protecting small abalones and their rearing. These results imply that the success of the ARP would be primarily dependent upon the selection of releasing site and effective management system after releasing.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.11
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• pp.1665-1674
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• 2013

In this paper, we propose a genetic algorithm(GA) based locomotion method of a quadruped robot with waist joint, which makes a quadruped robot walk on the slop efficiently. In the proposed method, we first derive the kinematic model of a quadruped robot with waist joint and then set the gene and the fitness function for GA. In addition, we determine the best attitude for a quadruped robot and the landing point of a foot in the walk space, which has the optimal energy stability margin(ESM). Finally, we verify the effectiveness of the proposed method by comparing with the performance of the previous method through the computer simulations.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.5
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• pp.57-63
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• 2009

A modeling and simulation program for an environmental control system (ECS) of a pod installed under wings of an aircraft was developed in order to estimate the system‘s performance during a flight. First, through the system configuration analysis in the main operational condition of the aircraft system, an ECS configuration adopting an air cycle machine (ACM) was selected. Therefore the modeling program was developed to simulate the ECS with an ACM. Second, the sensitivity analyses on performance variation of main components were conducted to complete the conceptual design of the ECS. A design point for the system and its components was obtained through the analysis with the modeling and simulation program. The design point for the system and components was obtained through the analysis with the modeling and simulation program. Third, in order to study the feasibility of the ECS configuration, off-design performances of the ECS on various flight conditions, such as take off, maneuver, cruise and landing etc were estimated. Dynamic characteristics were analyzed by transient performance evaluations.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.176-189
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• 2024

Vertical takeoff and landing (VTOL) is a core feature of unmanned aerial vehicles (UAVs), which are commonly referred to as drones. In emerging smart logistics, drones are expected to play an increasingly important role as mobile platforms. Therefore, research on last-mile delivery using drones is on the rise. There is a growing trend toward providing drone delivery services, particularly among retailers that handle small and lightweight items. However, there is still a lack of research on a structural definition of the VTOL drone flight model for multi-point delivery service. This paper describes a VTOL drone flight route structure for a multi-drone delivery service using rotary-wing type VTOL drones. First, we briefly explore the factors to be considered when providing drone delivery services. Second, a VTOL drone flight route model is introduced using the idea of the nested graph. Based on the proposed model, we describe various time-related attributes for delivery services using drones and present corresponding calculation methods. Additionally, as an application of the drone route model and the time attributes, we comprehensively describe a simple example of the multi-drone delivery for first-come-first-served (FCFS) services.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.1
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• pp.1-7
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• 2008

Submarine cable is the most important IT infrastructure for international communication across oceans. However, a cable fault rarely happens by ship's anchor, fishing gears, submarine earthquake, and so on, and we need to improve on repair time for the reducing expenses of cable repair ship as well as the stability of high-capacity submarine optical network. There are several kinds of cable faults such as Shunt fault, Cable cut, Open fault and Fiber break. When a fault is occurred, cable landing stations(CLS) have to analysis failure quickly and accurately to find the type and the location of a cable fault. During the repair period, CLS should swiftly perform the tests requested by cable repair ship. In order to make rapid progress on cable repair, CLS test technique is very important. So, in order to reduce the repair time, this paper is studying the CLS test techniques of locating a submarine cable fault and of checking the splicing point performed by cable repair ship.

• Water for future
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• v.13 no.2
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• pp.55-62
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• 1980

It is very important thing that the high tide prediction along the sea-side before the typhoon landing. In Korea, every year somewhere of the near sea-shore has been suffered much damages by the high tide during typhoon season, and the governement has to spend much of the reserved budget to rescue and reconstruction the damaged facilities in the seas-shore area. In this point of view, as none of the high tide prediction program in Korea, the author aims to develope this kind of study, so that this application program may dedicate the concerned organizations such as Ministry of Construction, Commerce and Industry, and Agriculture Forestry and Fishery, etc. Due to developed the software of high speed electronic computer in recently, the complicated numerical analysis can be solve very conviniently. So the author tries to prepare the high tide predecation program using the equation of motion and continous in the fluide dynamics by the constant time and distance of the differentation method. The input data for this program are the weather chart and depth data of the mattered bay, inner-sea or outer-sea. This program has been applied on the Pohan inner harbor as a model and find ort the program computation results is coincide with the observed values of "FRAN" typhoon in 1976 at the Pohang harbor.ng harbor.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.228-235
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• 2010

This paper deals with an autonomous flight controller design problem for a tilt-rotor aircraft in rotary-wing mode. The inner-loop algorithm is designed using the output-based approximate feedback linearization. The model error originated from the feedback linearization is cancelled within allowable tolerance by using single-hidden-layer neural network. According to Lyapunov direct stability theory, the adaptive update law is derived to run the neural network on-line, which is based on the linear observer dynamics. Moreover, the outer-loop algorithm is designed to track the trajectory generated from way-point guidance. Especially, heading and flight-path angle line-of-sight guidance are applied to the outer-loop to improve accuracy of the landing tracking performance. The 6-DOF nonlinear simulation shows that the overall performance of the flight control algorithm is satisfactory even though the collective input response shows instantaneous actuator saturation for a short time due to the lack of the neural network and the saturation protection logic in that loop.