• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.211-218
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• 1999

The traditional robot manipulators are actuated by continuous range of motion actuators such as motors or hydraulic cylinders. However, there are many applications of mechanisms and robotic manipulators where only a finite number of locations need to be reached, and the robot’s trajectory is not important as long as it is bounded. Binary manipulator uses actuators which have only two stable states. As a result, binary manipulators have a finite number of states. The number of states of a binary manipulator grows exponentially with the number of actuators. This kind of robot manipulator has some advantage compared to a traditional one. Feedback control is not required, task repeatability can be very high, and finite state actuators are generally inexpensive. And this kind of robot manipulator has a fault tolerant mechanism because of kinematic redundancy. In this paper, we solve the inverse kinematic problem of a binary parallel robot manipulator using neural network and test the validity of this structure using some arbitrary points m the workspace of the robot manipulator. As a result, we can show that the neural network can find the nearest feasible points and corresponding binary states of the joints of the robot manipulator

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1216-1223
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• 2008

Displacement control of earth retaining wall is recognized as the most important item for insuring the stability of ground in urban deep excavation site near by major structure such as subway etc. The field monitoring system is classified by two types as manual system and automatic system. The application case of latter type of field monitoring is increased because real time measurement is possible in automatic system and that is correspondent with the recent constructional trend. Though the automatic monitoring system is more useful and advanced than manual monitoring system, accuracy of the system is not verified sufficiently. It was examined that the reliance of automatic monitoring system in this paper through the comparison of monitoring result obtained three urban excavation site in which the each type of monitoring system was executed concurrently. Result of the examination is that the two types of monitoring system is generally alike in view of monitoring result, so the engineering reliance of automatic system was confirmed in case site. This task was researched in restricted case site, it is expected more precise analysis from security of more data monitored and progressive study.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.205-212
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• 1999

A three dimensional binary parallel robot manipulator uses actuators which have only two stable states and its structure is variable geometry truss. As a result, it has a finite number of states and fault tolerant mechanism because of kinematic redundancy. This kind of robot manipulator has some advantages compared to a traditional one. Feedback control is not required, task repeatability can be very high, and finite state actuators are generally inexpensive. Because the number of states of a binary robot manipulator grows exponentially with the number of actuators it is very difficult to solve and inverse kinematic problem. The goal of this paper is to develop an efficient algorithm to solve an inverse kinematic problem of three dimensional binary parallel robot manipulator using a backbone curve when the number of actuators are too much. We first derive the coordinate transformations associated with a three degree of freedom in-parallel actuated robot manipulator. The backbone curve is generated optimally by considering the maximum roll and pitch angles of the robot manipulator configuration and length of link. Then, the robot manipulator is fitted along the backbone curve with some criterion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2646-2659
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• 2017

Equipped with the advantages of flexible access control and fine-grained authentication, attribute based signcryption is diffusely designed for security preservation in many scenarios. However, realizing efficient key evolution and reducing the calculation costs are two challenges which should be given full consideration in attribute based cryptosystem. In this paper, we present a key-policy attribute based signcryption scheme (KP-ABSC) with delegated computation and efficient key updating. In our scheme, an access structure is embedded into user's private key, while ciphertexts corresponds a target attribute set. Only the two are matched can a user decrypt and verify the ciphertexts. When the access privileges have to be altered or key exposure happens, the system will evolve into the next time slice to preserve the forward security. What's more, data receivers can delegate most of the de-signcryption task to data server, which can reduce the calculation on client's side. By performance analysis, our scheme is shown to be secure and more efficient, which makes it a promising method for data protection in data outsourcing systems.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.101-111
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• 2014

Aviation safety is increasingly important to secure the safety of the Republic of Korea Air Force (ROKAF). A critical activity for enhancing aviation safety is to analyze an accident throughly and to identify causes that can explain it reasonably. The results of such a systematic accident investigation can be effectively used for improving information displays, task procedures, and training systems as well as for reorganizing team structure and communication control system. However, the current practice of analyzing aviation accidents in ROKAF is too superficial and simple to diagnose them systematically. Additionally, the current practice does not give a full consideration to human factors that have been identified as main causes of most of the aviation accidents. With this issue in mind, this study aims to suggest a new approach to analyzing aviation accidents related to human factors.The proposed method is developed on the basis of several models and frameworks about system safety, human error, and human-system interaction. Its application to forty-two human factors-related accidents, which have occurred in ROKAF during the last ten years, showed that the proposed method could be a useful tool for analyzing aviation accidents caused by human factors.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.174-179
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• 1999

A binary parallel robot manipulator uses actuators which have only two stable states and is structure is variable geometry truss. As a result, it has a finite number of states and fault tolerant mechanism because of kinematic redundancy. This kind of robot manipulator has the following advantages compared to a traditional one. Feedback control is not required, task repeatability can be very high, and finite state actuators are generally inexpensive. Because the number of states of a binary robot manipulator grows exponentially with the number of actuators, it is very difficult to solve an inverse kinematic problem. The goal of this paper is to develop an efficient algorithm to solve an inverse kinematic problem when the number of actuators are too much or the target position is located outside of workspace. The backbone curve is generated optimally by considering the curvature of the robot manipulator configuration and length of link. Then, the robot manipulator is fitted along the backbone curve with some criteria.

• Smart Structures and Systems
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• v.9 no.6
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• pp.535-547
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• 2012

Controlling the balance of motion in a context involving a biped robot navigating a rugged surface or a step is a difficult task. In the present study, a $3{\times}5$ flexible piezoelectric tactile sensor array is developed to provide a foot pressure map and zero moment point for a biped robot. We introduce an innovative concept involving structural electrodes on a piezoelectric film in order to improve the sensitivity. The tactile sensor consists of a polymer piezoelectric film, PVDF, between two patterned flexible print circuit substrates (FPC). Additionally, a silicon rubber bump-like structure is attached to the FPC and covered by a polydimethylsiloxane (PDMS) layer. Experimental results show that the output signal of the sensor exhibits a linear behavior within 0.2 N ~ 9 N, while its sensitivity is approximately 42 mV/N. According to the characteristic of the tactile sensor, the readout module is designed for an in-situ display of the pressure magnitudes and distribution within $3{\times}5$ taxels. Furthermore, the trajectory of the zero moment point (ZMP) can also be calculated by this program. Consequently, our tactile sensor module can provide the pressure map and ZMP information to the in-situ feedback to control the balance of moment for a biped robot.

• Asia-Pacific Journal of Business
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• v.12 no.2
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• pp.25-37
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• 2021

Purpose - This study analyzes the situational relationship between the components of job crafting and innovation performance, and based on this, suggests practical alternatives to the effect of the control variables of organizational support. Design/methodology/approach - For this survey, 350 questionnaires were distributed to Korean SME workers from October 5, 2020 to March 20, 2021, and 230 questionnaires were collected. In order to check the validity of the questionnaire, the questionnaire judged to be inappropriate in response was excluded. The recovery rate was 65.7%, and the effectiveness of the questionnaire was 82%. Structural equation model and hierarchical regression analysis are used to analyze those data. Findings - First, job enhancement through job redesign as well as organizational support is a key task in order to expect innovative results from field members. Innovative performance is not created by individual jobs, but is created between jobs and jobs, tasks and tasks, teams and teams, and departments and departments. This is why it is worth paying attention not to the functional approach, but to the interconnection structure of the process. Research implications or Originality - In this study, it was analyzed that structural job resource increase and social job resource increase, which are components of job crafting, had a positive effect on innovation performance, and that challenging job will had no significant effect. Challenging work will itself does not negatively affect innovation performance. Combining the survey and interview, field members who make up the majority of respondents say that they do not lack the will to work. They claim that there is no channel or opportunity to express or practice a challenging will.

• International Journal of Computer Science & Network Security
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• v.22 no.11
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• pp.199-203
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• 2022

The article aims at studying the institution of human rights and civil freedoms with due regard to the anthropological approach in the theory of law. To the greatest extent, the provisions of non-classical legal science are confirmed in the Anglo-Saxon legal family, which endows the judge with law-making functions. In this regard, the role of a person in the legal sphere is increasing. The main research method was deduction used to study the anthropological approach to the institution of human rights and freedoms. The article also utilizes the inductive method, the method of systematic scientific analysis, comparative legal and historical methods. To solve the task set, the authors considered the legal foundations and features of human rights and freedoms in the modern world. The article proves that the classical legal discourse, represented by various types of interpretation, reduces the rule of law to the analysis of its logical structure and does not answer the questions posed. It is concluded that the prerequisite for the anthropological approach in the theory of law is the use of human-like concepts in modern legislation (guilt, justice, peculiar ferocity, child abuse, willful evasion, conscientiousness).

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.2
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• pp.106-114
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• 2015

In the fabrication of offshore oil and gas facilities, the significance of dimension control is growing continuously. But, it is difficult to determine the deformation of the structure during fabrication by simple lab tests due to the large size and the complicated shape. Strain-boundary method (a kind of shrinkage method) based on the shell element was proposed to predict the welding distortion of a structure effectively. Modeling of weld geometry in shell element is still a difficult task. In this paper, a concept of imaginary temperature pair is introduced to handle the effect of geometric factors such as groove shape, plate thickness and pass number, etc. Single pass imaginary temperature pair formula is derived from the relation between the groove area and the FE mesh size. By considering the contribution of each weld layer to the whole weldment, multi-pass imaginary temperature is also derived. Since the temperature difference represents the distortion increment, cumulative distortion curve can be drawn by integrating the temperature difference. This curve will be a useful solution when engineers meet some problems occurred in the shipyard. A typical example is shown about utilization of this curve. Several verifications are conducted to examine the validity of the proposed methodology. The applicability of the model is also demonstrated by applying it to the fabrication process of the heavy ship block. It is expected that the imaginary temperature model can effectively solve the modeling problem in shell element. It is also expected that the cumulative distortion curve derived from the imaginary temperature can offer useful qualitative information about angular distortion without FE analysis.