• Journal of the Korea Society for Simulation
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• v.17 no.1
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• pp.33-42
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• 2008

In general, simulation is to predict or evaluate some systems that are hard to be executed in real world, and so usually the target systems to be modeled are large and complex. Trying to observe the dynamics of the systems results in similar level of animation complexity, the model and animation has the same complexity as the system. Trying to display all the graphic objects representing the dynamics of the models being simulated, however, causes the distraction of focus, which results in solving the above listed problems difficult. The redundant graphic objects also increase the computer computation overhead. To solve the problem, a research about a hierarchical animation environment has been proposed a few years ago. In the research, the users can have better focus on the dynamics of system components by selectively choosing the hierarchical level and components within a level of the hierarchically structured model. However, the research has not a modeling methodology for modelers to describe systematically animation part corresponding to dynamics of simulation in a model. This research has defined the modeling methodology of DESHA and defined DESHA-C++, improving the previous research output, as an execution environment of DESHA models. In addition, to use hierarchical animation environment in various problems, this research proposed and developed the distributed simulation modeling environment that connects DESHA environment and HLA.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.732-737
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• 2009

Due to various project delivery methods and the complexity of construction projects in the construction industry, developing the framework of construction management for critical, highly complex projects in the construction industry has become problematic. Currently, a set of construction manuals play a pivotal role in planning and managing construction projects as subcontractors try to complete their scope of work according to the instructions of a general contractor. It is challenging for general contractors to write a construction management procedure manual to cover various types of project delivery methods and construction projects. In construction, the construction procedure manuals describe specific actions to be taken through the project. In reality a few contactors own such manuals and their construction schedules include more construction operation activities. Thus, it is hard to estimate the workload and productivity of construction managers because the manual and the schedule do not present the amount of management efforts required to complete a project. This paper proposes a framework to present construction management tasks according to project delivery methods which can be applied to various construction projects. Actions for management tasks were mapped and were integrated with construction activities throughout the project life cycle. The framework can then be used to give specific instructions to project participants, collect management actions, and replicate management actions throughout the project life cycle. The framework can also be can used to visualize complete construction project to analyze and manage construction management activities in each phase of a project in order to enhance productivity and efficiency. The studies of existing construction manuals were carried out to identify construction managers' responsibilities. An artificial intelligence program, CLIPS (C-Language Integrated Production System) was used to search for appropriate actions for impending tasks from a set of predefined actions to be performed for a given situation. The framework would significantly help construction managers to understand interrelations among management tasks or actions within a project. Furthermore, the framework can be embedded into Building Information Modeling (BIM) or Facility Management Systems (FMS) so that designers and constructors would execute constructability review before construction begins.

• Journal of KIISE:Software and Applications
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• v.37 no.4
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• pp.323-339
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• 2010

The complexity of embedded systems and the effort to develop them has been rising in proportion with their importance. Also, the heterogeneity of the hardware and software parts in embedded systems makes it more challenging to develop. Errors caused by hardware/software interfaces, especially, account for up to 13 percent of failures with an increasing trend. Therefore, verifying the interface between hardware and software in embedded system is one of the most important research areas. However, current approaches such as co-simulation method and model checking have explicit limitations. In this paper, we propose the synthesizable interface co-verification framework for hardware/software co-design. Firstly, we introduce the separate interface specifications for the heterogeneous components to describe hardware design and software design. Our specifications are expressive enough to describe both. We also provide the transformation rules from the software specification to the hardware specification so that the whole system can be described from the software view. Secondly, we address the solution of verifying the interface of the software and hardware design by adopting and extending existing verification-techniques and extending them. In hardware interface verification, we exploit the model checking technique and provide more efficient verification by closing the hardware design from the assumption of the software behavior which is ensured by software verification step. Lastly, we generate the interface codes such as device APIs, device driver, and device controller from the specification so that verified hardware and software codes can be synthesized without extra efforts.

• Industrial Engineering and Management Systems
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• v.11 no.2
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• pp.155-164
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• 2012

As the global market becomes more competitive, manufacturing industries face relentless pressure caused by a growing tendency of greater varieties of products, shorter manufacturing cycles and more sophisticated customer requirements. Efficient and effective supplier selection and order allocation decisions are, therefore, important decisions for a manufacturer to ensure stable material flows in a highly competitive supply chain, in particular, when customers are willing to accept products with less desirable product attributes (e.g., color, delivery date) for economic reasons. This paper attempts to solve optimally the challenging problem of supplier selection and order allocation, taking into consideration the customer flexibility for a manufacturer producing multi-products to satisfy the customers' demands in a multi period planning horizon. A new mixed integer programming model is developed to describe the behavior of the supply chain. The objective is to maximize the manufacturer's total profit subject to various operating constraints of the supply chain. Due to the complexity and non-deterministic polynomial-time (NP)-hard nature of the problem, an improved genetic approach is proposed to solve the problem optimally. This approach differs from a canonical genetic algorithm in three aspects: a new selection method to reduce the chance of premature convergence and two problem-specific repair heuristics to guarantee feasibility of the solutions. The results of applying the proposed approach to solve a set of randomly generated test problems clearly demonstrate its excellent performance. When compared with applying the canonical genetic algorithm to locate optimal solutions, the average improvement in the solution quality amounts to as high as ten percent.

• Journal of the Ergonomics Society of Korea
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• v.25 no.3
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• pp.49-60
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• 2006

Technological encroachment provides human operators with flood of information that must be analyzed to understand the environment and make judgments that lead to strategic actions. Further, the environment is not static and therefore uncertain, changing its aspect dynamically. Complexity accompanied with its dynamics imposes substantial difficulty to human operators' task. Criticality of having situational understanding becomes more important than ever. Situationalunderstanding requires the human operators possessing tacit knowledge in order for them to make the sense out of the situation while interacting with information from many heterogeneous sources, the notion of sensemaking. Sensemaking refers to the process of developing mental framework to assemble pieces of information representing different aspects of the environment that can be used to develop one's own actionable knowledge to implement their judgments in the uncertain environment. Therefore, judgment process and performance is a key component of sensemaking process. Among many judgment and decision making models, the lens model with its extension can be utilized to partially describe the judgmental aspect of sensemaking. One of the lens model parameters, unmodeled knowledge, can be a corresponding quantitative measure for the tacit knowledge that plays an important role in sensemaking. In this paper, a comprehensive literature for sensemaking is provided to formally define the notion of sensemaking in the military domain. Also, it is proposed that there is a crucial link between the sensemaking and human judgment process and performance from the lens model perspective. Potential implications for experimental framework are also proposed.

• Archives of Plastic Surgery
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• v.40 no.3
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• pp.232-237
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• 2013

Background Polydactyly of the foot is one of the most frequent anomalies of the limbs. However, most classification systems are based solely on morphology and tend to be inaccurate and less relevant to surgical methods and results. The purpose of this study is to present our new classification of polydactyly of the foot, which can serve as a predictor of treatment and prognosis. Methods To find a correlation between the various morphologic traits of polydactyly of the foot and the treatment plan and outcomes, we reviewed 532 cases of polydactyly of the foot in 431 patients treated in our hospital, expanding on our previous study that described polydactyly based on the importance of metatarsal bone status and varus deformity. The records of patients were evaluated and compared with previous studies at other centers. Results Unsatisfactory results were seen in 36 cases, which included 5 cases of incomplete separation due to syndactylism, 23 cases of axis deviation, and 8 cases of remnants of extradigit metatarsal bones. The locus of the polydactyly, or the digit which was involved, did not seem to affect the final postoperative outcomes in our study. Three factors-syndactylism, axis deviation, and metatarsal extension-are the major factors related to treatment strategy and prognosis. Therefore, we developed a new classification system using three characters (S, A, M) followed by three groups (0, 1, 2), to describe the complexity of polydactyly of the foot, such as $S_1A_2M_2$. Conclusions Our new classification could provide a communicable description to help determine the surgical plan and predict outcomes.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.3
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• pp.186-189
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• 2003

Various empirical formulas have been developed to describe the stability of breakwater armor stones. The Hudson formula is known to have needs to be refined in many ways. but it is most widely used because of its simplicity. The van der Meer formula is sometimes used for the cross-check, but it is not very popularly used due to its complexity and the uncertainty of the relevant parameters. Recently, on the other hand, Yoo(2003) proposed a formula of a simple form using a new non-dimensional number which is called 'action slope' (abbreviated as Yoo formula hereinafter). In this study, in order to provide coastal engineers with some idea of the use of these formulas, their accuracies were estimated by comparing with the experimental data reported by van der Meer in 1987 and 1988. It was found that the van der Meer formula showed the highest accuracy, while the Hudson formula of very low accuracy needed considered judgment on its use. On the other hand, the Yoo formula of slightly lower accuracy but simpler expression than the van der Meer formula seems to be able to be used in engineering practice if a slightly higher safety factor is taken.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1299-1306
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• 2011

In this study, crack-growth model parameters subjected to variable amplitude loading are estimated in the form of a probability distribution using the method of Bayesian parameter estimation. Huang's model is employed to describe the retardation and acceleration of the crack growth during the loadings. The Markov Chain Monte Carlo (MCMC) method is used to obtain samples of the parameters following the probability distribution. As the conventional MCMC method often fails to converge to the equilibrium distribution because of the increased complexity of the model under variable amplitude loading, an improved MCMC method is introduced to overcome this shortcoming, in which a marginal (PDF) is employed as a proposal density function. The model parameters are estimated on the basis of the data from several test specimens subjected to constant amplitude loading. The prediction is then made under variable amplitude loading for the same specimen, and validated by the ground-truth data using the estimated parameters.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.353-356
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• 2007

With advances in sensor technology, current researches on the pertinent techniques are actively directed toward the way which enables the USN computing service. For many applications using sensor networks, the incoming data are by nature characterized as high-speed, continuous, real-time and infinite. Due to such uniqueness of sensor data characteristics, for some instances a finite-sized buffer may not accommodate the entire incoming data, which leads to inevitable loss of data, and requirement for fast processing makes it impossible to conduct a thorough investigation of data. In addition to the potential problem of loss of data, incoming data in its raw form may exhibit high degree of complexity which evades simple query or alerting services for capturing and extracting useful information. Furthermore, as traditional mining techniques are developed to handle fixed, static historical data, they are not useful and directly applicable for analyzing the sensor data. In this paper, (1) describe how three mining techniques (sensor data outlier analysis, sensor pattern analysis, and sensor data prediction analysis) are appropriate for the USN middleware structure, with their application to the stream data in ocean environment. (2) Another proposal is a middleware structure based on USN environment adaptive to above mining techniques. This middleware structure includes sensor nodes, sensor network common interface, sensor data processor, sensor query processor, database, sensor data mining engine, user interface and so on.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.1
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• pp.18-23
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• 2006

Recently as the power system has been becoming massive and complicated, most of the faults bring on severe proliferation effects. Because of the complexity of the power system it is not easy to analyze faults-the calculation of current flows under fault conditions. Therefore many researches have been performed in this area. As a result of those efforts, the protective equipments for a power system have been designed to operate properly and without damage when the highest possible fault current is flowing in the power system. Most of the fault data can be also acquired from intelligent protection equipments. The fault data saved in them don't always include the fault type information. n you don't have knowledge about the fault analysis, it becomes useless. So this paper presents 3 topics to increase a reusability of them as followings. First, describes a fault data using the XML(extensible Markup Language). It would be a well-formed and valid document complied with suggested XML DTD(Document Type Definition). In this paper I suggest a standard DTD to describe the power system fault. If the XML document describes any power system faults is validated against suggested DTD, it is possible to be used in any applications. Second, sends them through the web using the XML web service. Last, presents the rapid and accurate algorithm for a fault type determination of the fault data received from the web. In the ultimate the client to request the server to analyze a fault data is provided the correct information what kind of fault is occurred.