• Physical Therapy Rehabilitation Science
• /
• v.3 no.1
• /
• pp.69-75
• /
• 2014

Objective: We developed a Motor-Assisted Rowing Machine (MARM) for Spinal Cord Injury (SCI), by modification of the Concept II rowing machine, so that the seats could be operated automatically in a backward and forward direction by a motor. Design: Case report. Methods: Motor rowing consisted of a chair with inclination control, a motor system, control button, monitor, program, leg supporter, safety belt, and seat. The patients were 2 men rowing athletes with SCI, classified as American Spinal Injury Association class B, participated in the study. Level of thoracic injury ranged from T8 to T10. The subjects rowed at a self-selected stroke rate with 50 watts. Two different rowing methods (static rowing without movement of the seat, dynamic rowing using MARM) were assigned to each participant during 10 minutes; 34 reflective markers were attached to their full bodies. Kinematic data were collected using the Vicon motion analysis system. Based on the full body model provided as a default by the equipment. In the rowing exercise, the rowing motions were divided into Drive Phase and Recovery Phase. Results: The two rowing methods differ in handle range, seat range, handle and seat ratio, handle velocity, and seat velocity during static and dynamic rowing. The rowing exercise using a rowing machine developed MARM increased tendency to the range of motion in the dynamic method compared to the static method. Conclusions: The newly developed MARM could be a useful whole body exercise for people with SCI.

• Journal of Ocean Engineering and Technology
• /
• v.20 no.5 s.72
• /
• pp.57-62
• /
• 2006

The most important thing in acontainer terminal is to handle the cargo effectively in the limited time available. To achieve this objective, many strategies have been introduced and applied. To create an automated container terminal, it is necessary for the cargo handling equipment to be equipped with more intelligent control systems. From the middle of the 1990's, automated rail-mounted gantry cranes (RMGC) and rubber-tired gantry cranes (RTG) have been widely used to handle containers in yards. Recently, many pieces of equipment, like CCD cameras and sensors, have beenmounted in these cranes to cope with the automated terminal environment. In this paper, we try to support the development of more intelligent automated cranes, which allow for more effective cargo handling in yards. For this purpose, the modeling, tracking control, anti-sway system design, skew motion suppressing, and complicated motion control and suppressing problems must be considered. Especially, in this paper, the system modeling and a new tracking control approach are discussed, and an experimental study is performed based on a two-degree-of-freedom (2DOF) servosystem design.

• Journal of Ocean Engineering and Technology
• /
• v.20 no.6 s.73
• /
• pp.114-122
• /
• 2006

The most important thing in the container terminal is to handle the cargo effectively in a limited time. To achieve this objective, many strategies have been introduced and applied. If we consider the automated container terminal, it is necessary that the cargo handling equipment is equipped with more intelligent control systems. From the middle of the 1990s, an automated rail-mounted gantry crane (RMGC) and rubber-tired gantry crane (RTG) have been developed and widely used to handle containers in the yards. Recently, in these cranes, equipment like CCD cameras and sensors have been mounted to cope with the automated terminal environment. In this paper, we try to support the development of more intelligent automated cranes that make the cargo handling be performed effectively in the yards. For this plant, we ought to consider modeling, tracking control, anti-sway system design, skew motion suppressionand complicated motion control and suppressing problems. In this paper, the system modeling and a tracking control approach are discussed, based on a two-degree-of-freedom (2DOF) servo-system design. From the simulation results, the good control performance of the designed control system is evaluated.

• Journal of the Ergonomics Society of Korea
• /
• v.34 no.5
• /
• pp.447-454
• /
• 2015

Objective: The purposes of this study are to survey general and ergonomics relevant patents of major foreign countries, to classify the ergonomics patents into some categories frequently found in the patents lists surfed and to compare the results with those of Korea. Background: Under today's severe competitions between countries and between companies, the intellectual property has never been more important. It is needed to investigate Korea's positions and worldwide status of patent applications and grants for general and ergonomics patents. Method: This study was mainly based on relevant websites surfing such as KIPRIS, FPO, EPO, WIPO, etc. Results: The results showed that while Korea placed fourth in patent applications and grants in 2012, following US, Japan and China, Korea ranked seventh in the number of ergonomics patents. Of the overseas ergonomics patents, the proportion of tool/device was the second highest to category of others, followed by chair/desk, grip/handle and keyboard, etc. Compared to the overseas ergonomics patents, Korea showed a slightly different trend that there were less patents for specific fields of ergonomics such as grip/handle, keyboard, tool/device, etc. Conclusion: The number of ergonomics patents of Korea was behind most foreign countries surveyed in the number of patent applications and grants of, and there were many categories of overseas ergonomics patents. Application: This study would be used as a reference or guideline when developing varying ergonomic products or applying to ergonomics patents.

• Journal of Biosystems Engineering
• /
• v.40 no.3
• /
• pp.284-288
• /
• 2015

Training power tiller operators in safe farming is necessary to avoid farming accidents. With the continuing progress in computational technology, driving simulators have become increasingly popular for conducting such training. Purpose: The objective of this study is to develop mock control devices and data acquisition apparatus for a tiller simulator. Methods: Except for the stand and tail wheel adjusting levers, the mock control devices were developed using a tiller handle assay. The data acquisition apparatus was realized using an embedded data-logging device and LabVIEW, the system design software. Results: The control devices of a real handle assay were successfully mimicked by the mock operator control devices, which used sensors for the relevant measurements. The data from the mock devices were acquired and transmitted to the main computer at intervals of 10 ms via Wi-Fi. Conclusions: The developed mock control devices operate similar to real power tillers and can be utilized in power tiller training simulators.

• Nuclear Engineering and Technology
• /
• v.55 no.9
• /
• pp.3277-3290
• /
• 2023

Nuclear power plant (NPP) operations with multiple objectives and devices are still performed manually by operators despite the potential for human error. These operations could be automated to reduce the burden on operators; however, classical approaches may not be suitable for these multi-objective tasks. An alternative approach is deep reinforcement learning (DRL), which has been successful in automating various complex tasks and has been applied in automation of certain operations in NPPs. But despite the recent progress, previous studies using DRL for NPP operations have limitations to handle complex multi-objective operations with multiple devices efficiently. This study proposes a novel DRL-based approach that addresses these limitations by employing a continuous action space and straightforward binary rewards supported by the adoption of a soft actor-critic and hindsight experience replay. The feasibility of the proposed approach was evaluated for controlling the pressure and volume of the reactor coolant while heating the coolant during NPP startup. The results show that the proposed approach can train the agent with a proper strategy for effectively achieving multiple objectives through the control of multiple devices. Moreover, hands-on testing results demonstrate that the trained agent is capable of handling untrained objectives, such as cooldown, with substantial success.

• Industrial Engineering and Management Systems
• /
• v.12 no.4
• /
• pp.306-316
• /
• 2013

The semiconductor industry has grown rapidly, and subsequently production planning problems have raised many important research issues. The reentrant flow-shop (RFS) scheduling problem with time windows constraint for harddisk devices (HDD) manufacturing is one such problem of the expanded semiconductor industry. The RFS scheduling problem with the objective of minimizing the makespan of jobs is considered. Meeting this objective is directly related to maximizing the system throughput which is the most important of HDD industry requirements. Moreover, most manufacturing systems have to handle the quality of semiconductor material. The time windows constraint in the manufacturing system must then be considered. In this paper, we propose a hybrid genetic algorithm (HGA) for improving chromosomes/offspring by checking and repairing time window constraint and improving offspring by left-shift routines as a local search algorithm to solve effectively the RFS scheduling problem with time windows constraint. Numerical experiments on several problems show that the proposed HGA approach has higher search capability to improve quality of solutions.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2005.04a
• /
• pp.209-216
• /
• 2005

The controller that can control the smart base isolation system consisting of M damper and friction pendulum systems(FPS) is developed in this study. A fuzzy logic controller (FLC) is used to modulate the M damper force because the FLC has an inherent robustness and ability to handle non-linearities and uncertainties. A genetic algorithm (GA) is used for optimization of the FLC. When earthquake excitations are applied to the structures equipped with smart base isolation system, the relative displacement at the isolation level as well as the acceleration of the structure should be regulated under appropriate level. Thus, NSGA-II(Non-dominated Sorting Genetic Algorithm) is employed in this study as a multi-objective genetic algorithm to meet more than two control objectives, simultaneously. NSGA-II is used to determine appropriate fuzzy control rules as well to adjust parameters of the membership functions. Effectiveness of the proposed method for optimal design of the FLC is judged based on computed responses to several historical earthquakes. It has been shown that the proposed method can efficiently find Pareto optimal sets that can reduce both structural acceleration and base drift from numerical studies.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.4
• /
• pp.1508-1517
• /
• 2015

Optimal Power dispatch is the short-term decision of the optimal output of a number of power generation facilities, to meet the system demand, with the objective of Power dispatching at the lowest possible cost, subject to transmission lines power loss and operational constraints. The operational constraint includes power balance constraint, generator limit constraint, and emission dispatch constraint and valve point effects. In this paper, Opposition based Differential Evolution Algorithm (ODEA) has been proposed to handle the objective function and the operational constraints simultaneously. Furthermore, the valve point loading effects and transmission lines power loss are also considered for the efficient and effective Power dispatch. The ODEA has unique features such as self tuning of its control parameters, self acceleration and migration for searching. As a result, it requires very minimum executions compared with other searching strategies. The effectiveness of the algorithm has been validated through four standard test cases and compared with previous studies. The proposed method out performs the previous methods.

• Nuclear Engineering and Technology
• /
• v.49 no.2
• /
• pp.404-410
• /
• 2017

In order to help decision-makers in the early design phase to improve and make more cost-efficient system safety and reliability baselines of aircraft design concepts, a method (Multi-objective Optimization for Safety and Reliability Trade-off) that is able to handle trade-offs such as system safety, system reliability, and other characteristics, for instance weight and cost, is used. Multi-objective Optimization for Safety and Reliability Trade-off has been developed and implemented at SAAB Aeronautics. The aim of this paper is to demonstrate how the implemented method might work to aid the selection of optimal design alternatives. The method is a three-step method: step 1 involves the modelling of each considered target, step 2 is optimization, and step 3 is the visualization and selection of results (results processing). The analysis is performed within Architecture Design and Preliminary Design steps, according to the company's Product Development Process. The lessons learned regarding the use of the implemented trade-off method in the three cases are presented. The results are a handful of solutions, a basis to aid in the selection of a design alternative. While the implementation of the trade-off method is performed for companies, there is nothing to prevent adapting this method, with minimal modifications, for use in other industrial applications.