• Speech Sciences
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• 제8권3호
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• pp.133-142
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• 2001

In the area of speech processing, raw signals used to be presented in 2D format and different kinds of algorithms use the format to solve their problems. However, such kinds of presentation methods have limitations to extract characteristics from the signal, even though the algorithms are quiet good. The basic reason is that not much information can be detected from the 2D signal. Strange attractor in the field of chaos theory provides the 3D presentation method. In the area of the recognition problem, signal construction method is very important because good features can be detected from a good shape of attractors. This paper discusses a new presentation method that can be used to construct strange attractor in a different way. Normal strange attractor uses time-delay idea while the new method uses time-delay and vector average. This method provides us good information to be applied to speaker recognition problem.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제25권7호
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• pp.1097-1106
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• 2001

A telescopic handless is a kind of construction machinery for loading, carrying and unloading various cargos. A residual vibration of the boom, however, is often caused in carrying cargos to high workplace, especially in small motion and unloading operations, even when an expert of this machine handless the boom. To solve this vibrational problem, we applied TDC and newly proposed Commandless IST to the telescopic handler, and confirmed their effectiveness through experiments. These promising results show that the proposed control schemes can improve productivity, safety and ride comfort of the telescopic handler.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제60권11호
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• pp.2119-2130
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• 2011

This paper proposes new delay-dependent robust stability criteria for neural networks with time-varying delays. By construction of a suitable Lyapunov-Krasovskii's (L-K) functional and use of Finsler's lemma, new stability criteria for the networks are established in terms of linear matrix inequalities (LMIs) which can be easily solved by various effective optimization algorithms. Two numerical examples are given to illustrate the effectiveness of the proposed methods.

• Korean System Dynamics Review
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• 제6권2호
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• pp.25-35
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• 2005

This paper describes the mechanism for new investment to appear in waves of boom and bust causing alternative periods of over and under supply of electricity in Korean market. A system dynamics model was developed to describe the dynamic behavior of new investment in Korean market. The simulation results show the boom and bust cycle in the new investments. When the market price is high, investors decide to build new power plants. However, it takes some delay time to complete new power plants. When the new power plants are being added into the grid, the supply increases and the wholesale price begins to decrease. This causes the cancellation of new power plant or delay the construction. This mechanism causes the boom and bust cycle in new investment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.115-117
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• 2012

Task based modeling is essential in a construction operation simulation modeling. It allows dealing with local variables or delay factors that affect productivity and improves the reusability of existing operation models. An operation model can secure reality only if it reflects the real construction processes by effectively dealing with zoning issue. However, system users have some difficulties in modeling a construction operation that is consisted of several processes having different production units. Zoning is a major modeling issue when the task based modeling method is implemented using the existing discrete event simulation systems. This paper highlights the difficulty and presents a new method that complements the zoning issues attributed to different production units. The method is described in detail by presenting the flow of entities. It is confirmed that the zoning method effectively deals with the unbalance of production units between processes and facilitates to model an operation model having processes with different production units. The "Zoning module" contributes to increasing accuracy of simulation result.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 한국건설관리학회 2002년도 학술대회지
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• pp.341-344
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• 2002

Claims are on an increasing trend in the domestic construction field with changes of negative thought about them. But there are still many factors of causing disputes Potentially due to old customs that an owner is predominant over a contractor. Unless these factors are solved, it is obvious that many disputes will occur henceforward. This study derives claim factors that must be solved first of all through analyzing how claim factors influence construction management factors such as time, cost, quality, and presents countermeasures that may prevent these claims.

• Journal of the Korea Institute of Building Construction
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• 제12권3호
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• pp.299-314
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• 2012

One of reasons for introducing Building Information Modeling (BIM) is to support clash detection tasks by means of a 3D product model. In the conventional construction project process, clashes have been found during construction phase. However, it can cause cost overrun and time delay. In order to investigate and correct clash detections at design phase, relevant business process and guide for this task should be provided. This study aims to identify hindrances in clash detection tasks at the design phase and analyze its current process using IDEF0 model. Despite the convenience of IDEF0 as a systems analysis tool, professional participants might have difficulties to understand their own tasks according to business process. For this reason, in this research, Business Process Model and Notation (BPMN) is introduced to provide ideal process and required decision making governance. The provide BPMN model will provide insights for a BIM-based collaborative environment to enhance the constructability through the construction project.

• Journal of Construction Engineering and Project Management
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• 제3권4호
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• pp.20-25
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• 2013

Variation in construction means modification of design, changes in quality, quantity of work including the alteration of standard of materials or goods to be used in the work and the removal from site any kind of material not in accordance in the contract. In Ghana, Variation order has become major issue in the construction industry. This had resulted in cost overruns, delay and in some contracts dispute, between parties. The aim of this paper was to identify the root causes of variation; effects of variations on projects in Ghana and the means of reducing the impact of variation order. The method of the study involved literature review, primary data collection, interview and closed - ended- questionnaires. Mean Scores Method was used to rank the identified factors causing variation. Analysis Of Variance Test was use to test for the significant difference between means among the professional groups. The study revealed that most causes of variation were change of design by client and inadequate working details. Establishment of oversight project management committee and flow of information were identified as means of controlling variations during project administration.

• The Korean Journal of Food & Health Convergence
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• 제5권6호
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• pp.11-16
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• 2019

The construction environment has been declared as a hazard prone area due to high number of accident and death. The study aims to identify influential factors that contribute to poor safety practices and its consequences on construction workers in Cape Coast Metropolis. Seventy respondents were taken as the sample size for the study. Descriptive analysis was used to analyze the data obtained from the field. Findings show that poor site management, working without safety gadgets, failure to use their Personal Protective Equipment (PPE) and negligence of workers were the main causes of accidents on sites. Poor site management had the highest ranking among the seven variables. Effects of poor safety practices on building construction site and delays in work execution were due to injury of workers, extra cost due to payment of compensation to injured victims, not motivated due to injury of worker and declined reputation of firm. Management team should motivate workers for safe work done, provide adequate PPE for their workers on site and have documented health and safety policy on site. Site authorities and management team should be on site regularly to ensure proper safety practices on construction site.

• International conference on construction engineering and project management
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.77-81
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• 2015

The unit price contracting is the standard contracting method for highway projects in the U.S. As a result, state highway agencies have collected a large amount of historical bid data that they can use to determine engineer's estimates for future projects. The estimator must carefully consider various characteristics of a new project such as its location to determine an engineer's estimate as accurate as possible before bid letting. Higher cost estimates can result in the loss of the available budget and lower cost estimates may lead to deferral and delay of projects. The study uses the historical bid data obtained from Iowa Department of Transportation and develops a Geographic Information System (GIS) tool to visually show the variation of unit prices over the map using a spatial interpolation technique. The interpolation map can be used to estimate the unit price of the item at any location across Iowa. This noble method allows the estimator to effectively and fully utilize the historical bid data in a very time efficient manner and determine more accurate cost estimation.