• Journal of Korean Institute of Industrial Engineers
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• v.15 no.1
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• pp.1-15
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• 1989

In the past few years, increasing numbers of automatic storage/retrieval system (AS/RS) using computer controlled storage/retrieval machine have been installed. This paper introduces two modeling approaches to determine the best operating policy for AS/RS : an M/G/1 queueing model and a computer simulation model. The operating policy consists of three elements. : the operation command cycle, the storage location method, and the operation dispatching rule. The analysis based on M/G/1 model is suitable for a quick and approximate evaluation, due to its inherent strict assumptions. The computer simulation can be used to perform a more realistic analysis. It is shown through the study that a significant improvement in the throughput and/or the space requirement can be expected by determining the best operating policy to a particular system. Most important, the computer simulation demonstrates its powerful capability in evaluating dynamic stochatic systems with imperfect information.

• Land and Housing Review
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• v.11 no.1
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• pp.103-108
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• 2020

Autonomous things system is a technology that judges and acts based on using surrounding information by itself, and it is evaluated as a future technology that can replace the current IoT technology. The current IoT technology is widely used from facility monitoring to machine control but it is shown weakness as a evaluation and prediction technique despite of smart city important technology. In this study, in order to confirm the application of the autonomous things technology, a monitoring system was installed on a real reservoir dam facility and long-term monitoring was performed that the measuring device itself judges and control as a facility monitoring technology. The autonomous things technology was confirmed during 19 months and it is possible to continuous measurement in the same way as current automated instrumentation. In addition, it was confirmed that the ICT device itself could to control autonomously measurement cycle according to the rainfall by itself.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.964-970
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• 2012

Various eco-design tools have been developed which can be classified into quantitative, semi-quantitative, and qualitative tools. Practitioners are reluctant to utilize quantitative tools in light of their time-demanding nature. Among the qualitative tools, checklists are simple tools that allow a quick and effective evaluation and consideration of environmental impacts over the entire life cycle of a product. A profound and better understanding of eco-design checklists is needed so that practitioners can apply them appropriately to their product development context. Various types of eco-design checklists are analyzed in the present study based on their attributes and classified in a structured way for their efficient utilization in product development contexts.

• Journal of Information Technology Services
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• v.7 no.4
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• pp.179-198
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• 2008

It is widely known that usability is a critical quality attribute of IT systems. Many studies have developed various methods for finding out usability problems. Usability professionals have emphasized that usability should be integrated into the development life cycle in order to maximize the usability of systems with minimal cost. To achieve this, it is essential to classify usability problems systematically and connect them into the activities of designing user interfaces and tasks. However, there is a lack of framework or method for these two problems and thus remains a challengeable research issue. As a beginning study, this paper proposes a conceptual framework for addressing the two issues. We firstly summarize usability-related studies so far, including usability factors and evaluation methods. Secondly, we review seven approaches to identifying and classifying usability problems. Based on this review and opinions of usability engineers in real industry as well as the review results, this paper proposes a framework comprising three viewpoints, from which more sound classification scheme of usability problems can be inductively developed.

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.133-141
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• 2015

This study tried to identify the problems associated with the posture to be analyzed and tried to suggest guidelines for MSDs(Musculoskeletal Disorders) evaluation based on working posture. A total of 50 jobs from 3 different types of industries(electronics, hospitals, automobiles) were used for MSDs evaluation study which was done by 6 observers. Two indexes were applied to identify the problem in this study which were percentage of agreement and counter-time-error rate. Specifically, 'counter-time-error rate' represented a degree of consistency in terms of selecting the posture to be analyzed time after time. Main results of the study were as follows; 1) The average percentage of agreement for representative posture for whole body was relatively higher than that for representative postures for individual body parts, 2) The counter-time-error rate(%) has been reduced as the evaluation process has repeated for the same job. 3) The counter-time-error rate(%) for electronics, hospitals, and automobiles were 63.4%, 61.2%, and 67.3% respectively. 4) The counter-time-error rate(%) for the job with the work cycle of 0.5 to 2 minutes were lower than that of the jobs with the work cycles less than 0.5 minute or greater than 2 minute. 5) The work cycles and the number of trials had significant effects on counter-time-error rate while the types of industries did not have significant effects on counter-time-error rate. Some guidelines could be prepared from the results of the study. Probably, there should have an extension in terms of form and matter for this study in order to have more practical output.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.59-65
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• 2012

In this paper, we proposed a method for automatic detection of a updating object from spatial data sets of different scale and updating cycle by using areal feature matching based on shape similarity. For this, we defined a updating object by analysing matching relationships between two different spatial data sets. Next, we firstly eliminated systematic errors in different scale by using affine transformation. Secondly, if any object is overlaid with several areal features of other data sets, we changed several areal features into a single areal feature. Finally, we detected the updating objects by applying areal feature matching based on shape similarity into the changed spatial data sets. After applying the proposed method into digital topographic map and a base map of Korean Address Information System in South Korea, we confirmed that F-measure is highly 0.958 in a statistical evaluation and that significant updating objects are detected from a visual evaluation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.1 s.256
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• pp.26-35
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• 2007

The vehicle of urban transit is a complex system that consists of various electric, electronic, and mechanical equipments, and the maintenance cost of this complex and large-scale system generally occupies sixty percent of the LCC (Life Cycle Cost). For reasonable establishing of maintenance strategies, safety security and cost limitation must be considered at the same time. The concept of system reliability has been introduced and optimized as the key of reasonable maintenance strategies. For optimization, three preceding studies were accomplished; standardizing a maintenance classification, constructing RBD (Reliability Block Diagram) of VVVF (Variable Voltage Variable Frequency) urban transit, and developing a web based reliability evaluation system. Historical maintenance data in terms of reliability index can be derived from the web based reliability evaluation system. In this paper, we propose applying inverse problem analysis method and hybrid neuro-genetic algorithm to system reliability optimization for using historical maintenance data in database of web based system. Feed-forward multi-layer neural networks trained by back propagation are used to find out the relationship between several component reliability (input) and system reliability (output) of structural system. The inverse problem can be formulated by using neural network. One of the neural network training algorithms, the back propagation algorithm, can attain stable and quick convergence during training process. Genetic algorithm is used to find the minimum square error.

• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.239-245
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• 2021

Due to the fourth industrial revolution and the Corona19, the availability of digital devices such as kiosks is a matter directly related to survival for older adults with digital divide. This paper analyzes the problems of existing information service education for older adults and proposes an IT education strategy tailored to aging and life cycle of older adults. The proposed in this study is an educational application-based IT training method that supports repetitive learning regardless of time and place, developing kiosk function as a functional game-type educational application and experimenting with post-training effectiveness. The research method proposed UI usability evaluation frame for older adults, and developed educational applications based on proposed evaluation frame, and conducted kiosk education. As a result of the experiment, the mission success rate after using the IT application was 80.6%, which is a 55.1%P improvement compared to the pre-use(25.5%). This study confirmed that the proposed education for older adults is a way to overcome the limitations of existing IT education in the current situation.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.73-78
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• 2015

Purpose : Under the assumption of change to the amplitude based sorting, the study will use four dimensional computed tomography imaging (4DCT) arrayed using the phase based sorting to analyze the respiratory phase difference. Materials and Methods : The study analyzed the 4DCT (4-dimensional computed tomography) images of 10 liver cancer patients that were treated with respiratory gated radiotherapy from 2015 February to March. Using RPM respiratory gating (RPM 1.7.5, Varian, USA) equipment, imaging according to respiratory cycle of phase based sorting was acquired and using a treatment planning system (Pinnacle 9.2, Philips, USA) the acquired imaging according to respiratory cycle was used to measure the abdominal movement value by respiratory cycle. The measuring point was the point where the center point of the Marker Block and the body surface met in the 50% phase image and here the coordinate values Lateral, Vertical, Longitudinal (X, Y, Z) were set as reference points, and on the X, Z plane identical to the reference point, using the identical method the Y axis coordinate value of each 0%, 30%, 40%, 50%, 60%, 80% phase images were acquired to quantitatively measure the variation of distance to the Y axis. The abdominal movement value according to respiration was applied to the theoretical model that the value decreases linearly from maximum inhalation to maximum exhalation to divide the variation of my value to predict as amplitude value by respiratory cycle and conversely the variation in amplitude was recalculated with the phase variation deviation value to analyze. Results : The deviation value between expected value and actual location was the largest in the 30% phase with 0.24 cm, and standard deviation was also the largest in 30% phase with 0.13 cm. The effective value of the deviation value derived from the average of the deviation squared value of each patient appeared as minimum 0.7 cm, maximum 0.18 cm, average 0.12 cm, and standard deviation 0.4 cm. Also by dividing the actual movement distance value with the peak expiration value then converting it into %Phase, the deviation value with actual phase 16.5% in 30% phase, 10.0% and 40% phase, 10.0% and 60% phase, 15.4% and 80% phase, and overall average about 13%, and arraying based on amplitude, phase shift occurred and further it was from peak expiration the chance of deviation occurrence was increasingly measured. Conclusion : Based on the results of the study there were differences between value acquired based on theoretical model and actual value. Therefore in respiratory gated radiotherapy using external surrogates, there needs to be establishment of respiration gated radiation system that avoids the combination of two Sorting methods considering that there will be occurrence of treatment and corresponding clinical differences due to the phase difference that occur due to the Amplitude based Phase Sorting.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.23-30
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• 2017

In the AEC(Architecture, Engineering and Construction) industry, BIM(Building Information Modeling) technology not only helps design intent efficiently, but also realizes an object-oriented design including building's life cycle information. Thus it can manage all data created in each building stage and the roles of BIM are greatly expanded. Contractors and designers have been trying to adopt BIM to design competitions and validate it for the best result in various aspects. Via the computational simulation which differs from the existing process, effective evaluation can be done. For this process, a modeling guideline for each kind of BIM tool and a validation system for the confidential assessment are required. This paper explains a new process about design evaluation methods and process using BIM technologies which follow the new paradigm in construction industry through complement points by an example of a competition activity of the Korea Power Exchange(KPX) headquarter office. In conclusion, this paper provides a basic data input guideline based on open BIM for automatic assessment and interoperability between different BIM systems and suggests a practical usage of the rule-based Model Checker.