• Advances in robotics research
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• v.2 no.2
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• pp.151-159
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• 2018

The evolution of bipedal robots was the foundation stone for development of Humanoid robots. The highly complex and non-linear dynamic of human walking made it very difficult for researchers to simulate the gait patterns under different conditions. Simple controllers were developed initially using basic mechanics like Linear Inverted Pendulum (LIP) model and later on advanced into complex control systems with dynamic stability with the help of high accuracy feedback systems and efficient real-time optimization algorithms. This paper illustrates a number of significant mathematical models and controllers developed so far in the field of bipeds and humanoids. The key facts and ideas are extracted and categorized in order to describe it in a comprehensible structure.

• The Journal of Fisheries Business Administration
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• v.22 no.1
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• pp.77-100
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• 1991

This study has made an attempt to analyze the determinants of Foreign Direct Investment (FFI) by Korean Fishery firms. The questionaire survey on individual firm's recognition and the determinants of Foreign Fishery Investment (FFI) was performed, yielding the following results. First, the main object of FFI is to reserve fishing ground. The result of the statistical analysis shows that import ratio for domestic market (DOM) is a significant variable of FFI. These two facts indicate our FFI is resouree-oriented in terms of the object and motive. Second, FFI is primaily determined by firm-related factors rather than country- related factors. The significant variable in firm-related factfors is the number of departments of the investing firm (DEPT). Another notable result is that fishing fee is not an influential variable in FFI decision.

• International Journal of Control, Automation, and Systems
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• v.3 no.3
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• pp.502-507
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• 2005

The dual-mode strategy has been adopted in many constrained MPC (Model Predictive Control) methods. The size of stabilizable regions of states of MPC methods depends on the size of underlying feasible and positively invariant sets and the number of control moves. The results, however, may perhaps be conservative because the definition of positive invariance does not allow temporal departure of states from the set. In this paper, a concept of periodic invariance is introduced in which states are allowed to leave a set temporarily but return into the set in finite time steps. The periodic invariance can be defined with respect to sets of different state feedback gains. These facts make it possible for the periodically invariant sets to be considerably larger than ordinary invariant sets. The periodic invariance can be defined for systems with polyhedral model uncertainties. We derive a MPC method based on these periodically invariant sets. Some numerical examples are given to show that the use of periodic invariance yields considerably larger stabilizable sets than the case of using ordinary invariance.

• Magazine of the Korea Concrete Institute
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• v.3 no.1
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• pp.87-94
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• 1991

Many different damage models have been prolxlsed for concrete in the past. Most of these are not well suited to predict the residual strength of damaged RC members. This paper reviews some basic facts alxlut concrete damage and uses these to systematically model damage as a low-cycle fatigue phenomenon. Instead of the number of load cycles to failure the energy dissipation capacity of a member is taken as the main variable, which depends on many different factors. The model is capable of simulating reasonably well the strength and stiffness degradation of I{C members subjected to strong cyclic loads.

• Korean Journal of Child Studies
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• v.30 no.6
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• pp.323-336
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• 2009

There has been a significant increase in the number of divorced families during the past 10 years in Korea. Divorce imposes a great impact on their children as well as divorcees. As many as 1.41 million children under 20 years-old have experienced their parents' divorce in past 10 years. Children are faced with much difficulty in adjustment after the parental divorce. Issues of the research and policy on the divorced family are discussed in this study. For future studies, a longitudinal research model, father-custody and grandparent-custody families, custody parents's gender, a theoretical model for Korean divorced families should be considered. New legislations have been recently enacted to enhance children's well-being, but further efforts such as the involvement of child development specialists in the divorce process should be followed in the pursuit of the best interest of the children.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.15-21
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• 1997

Pneumatics is widly used in the industrial implementation, in the operation of air-powered actuators and the control devices needed in their operation. However, there are many empirical factors in pneumatics design, it might cause excessive design of pneumatic components. For that reason, we developed VDES(Vacuum Design Expert System) for the economic design of pneumatic vacuum equipment. VDES is achieved with CLIPS(C Language Integrated Production System) and knowledge base that contains a number of facts and rules for pneumatic vacuum design. Forward chaining and depth first search technique are used in this system. Appling VDES to the actual field, this system is verified to be a good efficiency and could be applied to the field of pneumatic vacuum equipment design.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.456-464
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• 2017

The epigraphy is a text on metal or a text on stone. The value of epigraphy can be used to identify historical facts of the past. It is a good record to understand the past life and culture. But it is difficult to decode the character of the epigraphy which has been exposed to the outdoor for a long time. In this study, the proposed techniques are consisted of 3 parts: (1)The surface division into information area, non- information area, and undifferentiated area. And then, (2) The selection of points in the non-information area and finding a reference plane with the minimum error. (3) Flattening the points perpendicular to the reference plane and decoding characters on information area. This research contributes to narrow the scope of a particular letter and to read the controversial letters on the Pohang Jungsoengri Silla Stone Monument(Korea's national treasure number 318).

• Journal of the Korean Institute of Navigation
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• v.9 no.2
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• pp.13-26
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• 1985

The purpsoe of automatic steering system is to keep the ship's course stable with the minimum course error and rudder angle, and there have been a number of studies as to the optimal design and adjustment of the autopilot. Recently, modern control theories are being used widely in analyzing and designing the system. When a ship is at sea, autopilot installed on the ship plays an important role, particularly in the respect of economic aspects, that is, when the design and the adjustment of adjustable parameters are not conducted perfectly, the amount of loss in energy and the extension of sailing distance become large. Therefore the optimal design and adjustment of a autopilot are very important. Though P.I.D type autopilots are widely spread and generally used in modern ships, the suitability and the adjusting method are not clarified. In this paper the authors considered the stabilaity and the economical efficiency of the P.I.D. type autopilot and investigated various facts which should be considered at the time of designing and using the P.I.D. type autopilot through the digital computer simulation.

• Journal of Korean Society of Rural Planning
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• v.13 no.3
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• pp.91-101
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• 2007

Recently the number of rural development plans are increased and projects supported by government are various. These makes rural plans important. But there are many gaps between proposed plan and implementation. These gaps were wasteful in terms of resource management. This study examines differences between plan and implementation and the reasons why they are occurred. For this purpose, we did a case study which is focused on the four-year implementation of 2004-2006 "Unique Experience Village Master Plan" of Seochon, Chungbuk. As a result, we verified facts of gaps and causes, and two major causes were detected : one is the absence of operating and managing body(such as promoter of project, village leader, residences), and the other is inadequate master plan.

• International Journal of Fluid Machinery and Systems
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• v.2 no.3
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• pp.239-247
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• 2009

Sewage pumps are designed with a wide flow channel by, for example, sacrificing some efficiency and reducing the number of blades, in order to prevent plugging with foreign bodies. However, the behavior of foreign bodies which actually flow into a pump is extremely complex, and there are questions about whether the presumed foreign bodies will actually pass through. This paper proposes a new type of sewage pump impeller designed to further improve pump efficiency and performance in passing foreign bodies. This sewage pump impeller has a structure in which the suction flow channel of a closed type non-clog pump is wound in a helical spiral. The focus of this research was to investigate pump performance and internal flow in this single blade sewage pump impeller. The results clearly indicated the following facts: The developed sewage pump impeller exhibits high efficiency over a wide range of flow rates; internal flow of the pump is very complicated; and the internal flow state varies greatly when the flow rate changes.