• International conference on construction engineering and project management
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• 2022.06a
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• pp.1255-1255
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• 2022

Recently, research on digital twins to generate digital information and manage construction in real-time using advanced technology is being conducted actively. However, in the construction industry, it is difficult to optimize and apply digital technology in real-time due to the nature of the construction industry in which information is constantly fluctuating. In addition, inaccurate information on the topography of construction projects is a major challenge for earthmoving processes. In order to ultimately improve the cost-effectiveness of construction projects, both construction quality and productivity should be addressed through efficient construction information management in large-scale earthworks projects. Therefore, in this study, a 3D digital map-based AR site management work support system for higher efficiency and accuracy of site management was proposed by using unmanned aerial vehicles (UAV) in wide earthworks construction sites to generate point cloud data, building a 3D digital map through acquisition and analysis of on-site sensor-based information, and performing the visualization with AR at the site By utilizing the 3D digital map-based AR site management work support system proposed in this study, information is able to be provided quickly to field managers to enable an intuitive understanding of field conditions and immediate work processing, thereby reducing field management sluggishness and limitations of traditional information exchange systems. It is expected to contribute to the improvement of productivity by overcoming factors that decrease productivity in the construction industry and the improvement of work efficiency at construction sites.

• Proceedings of the CALSEC Conference
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• 1998.10b
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• pp.415-422
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• 1998

The international standard STEP for representation and exchange of product model data, and CORBA as a standard for distributed object computing environment are expected to play very important role in the future manufacturing environment. Platform independent network programming language Java is also becoming a standard environment for developing Internet/Intranet applications. Furthermore, the ObjectWeb environment supported by the combination of CORBA and Java technology provides very efficient and convenient way of developing network applications and user interfaces. In this research, we developed a framework for the real time sharing of STEP data and 3D conference in the ObjectWeb environment and tested our proposal by implementing prototype software which we call STEPShare.

• IE interfaces
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• v.11 no.1
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• pp.155-163
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• 1998

In multiparty multimedia communication, each participant not only receives information from other participants but also generates real-time data streams to distribute to others and therefore the difference between source and destination is not clear in terms of data transmission. During a teleconference session, many sub-multicast trees may be generated to exchange information to specific members within the multicast group and if those sub-multicast trees use the same fixed multicast tree, the blocking probability will be high and it is hard to provide QoS for each sub-multicast group. Also, even though there exits some shortcuts between each sub-multicast group, fixed multicast tree does not allow to use those shortcuts. Thus to overcome these problems. We propose a network resource reservation protocol and show that its effectiveness in terms of blocking probability and network resources usage.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.13-17
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• 1996

This paper presents animation techniques and issues involved in virtual environments where the participants interact with each other through a network. The state of the participant should be recognized at each local site, and broadcast to the other sites. Because information exchange is minimal, animation techniques are applied to convert the incoming low DOF parameters into high DOF joint angles that completely determine the configuration of the agents at each frame. As a case study, a software system VRLOCO is introduced, which has been developed by the author over the last five years. From a simple stream of body center positions, VRLOCO generates realistic curved path human locomotion in real-time. Based on the heading direction and speed, the locomotion automatically switches among five different primitives: walking, running, lateral stepping, backward stepping, and turnaround. The techniques presented here proved robust and faithful: the algorithm is not sensitive to the noise in the data, and the resulting animation conforms well with the original data.

• Journal of the Korean Society of Systems Engineering
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• v.1 no.1
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• pp.46-52
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• 2005

The Tactical Data Link System(TDLS) is a standardized communication link to exchange and interface positional, situational information, command and control in real time. It has been evalua ted that the link would play an important role for tactical interoperability, situation awareness, and execution of joint operations in the future war. But considering the rapidly changing war situations, even though being admitted the necessity of the TDLS of Army helicopter, one of superpowers in the Army, it is not yet built the detailed operational concept. Therefore, this work presents how to embody the TDLS through the systems engineering approach based on the TDLS operating concept analysis of helicopters-ground units.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.438-440
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• 2003

This paper resents an application of an Artificial Neural Network(ANN) technique to forecast the short-term system marginal price(SMP). The forecasting of SMP is a very important factor in an electricity market for the optimal biddings of market participants as well as for the market stabilization of regulatory bodies. The proposed neural network scheme is composed of three layers. In this process, input data are set up to reflect market conditions. And the $\lambda$ that is the coefficient of activation function is modified in order to give a proper signal to each neuron and improve the adaptability for a neural network. The reposed techniques are trained validated and tested with the historical real-world data from korea Power Exchange(KPX).

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.76-81
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• 2002

The characteristics of the track are important concerning the mobility of tracked vehicles. It can be represented in terms of the track tension and maintaining the track tension adequately guarantees the stable and improved driving of the tracked vehicles. The track tension must be known in order to be controlled and it needs to be estimated in real-time because it is difficult to be measured. The tension around idler and sprocket can be controlled by the frizzy logic control system base on the estimated values. Dynamic Track Tensioning System(DTTS) which is estimating and controlling the track tension. In this paper, simulation tool is developed in order to apply the DTTS to real battle tanks. To construct the simulation tool, the Modeling the tracked vehicle, constructing estimation system, and designing controller should be achieved first and then all subsystem should be organized in one. The simulation tool make the RecurDyn model of tracked vehicle, which is plant model, and the control system exchange their data simultaneously. Simulation with many kinds of driving conditions and road conditions is carried out and the results are interpreted. The interpretation provides necessary information to apply the DTTS to real battle tanks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1129-1137
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• 2012

The wireless link of tactical datalink system provides a communication network to share digitalized tactical data in real-time. Also MAC(Multiple Access Control) of this system is subject to TDMA or CSMA according to a operated circumstance of target nodes to exchange the data reliably. In this paper, we verify the operability when we use CSMA scheme based on MIL-STD-188-220 in tactical datalink system which is basically designed with TDMA, and provide a mathematical analysis scheme to verify the operability and performance. Finally, by implementing CSMA scheme to a tactical datalink equipment we obtain practical results which can be compared with theoretical results.

• International journal of advanced smart convergence
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• v.5 no.1
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• pp.34-46
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• 2016

Networked Control System (NCS) has evolved in the past decade through the advances in communication technology. The problems involved in NCS are broadly classified into two categories namely network issues due to network and control performance due to system network. The network problems are related to bandwidth allocation, scheduling and network security, and the control problems deal with stability analysis and delay compensation. Various delays with variable length occur due to sharing a common network medium. Though most delays are very less and mostly neglected, the network induced delay is significant. It occurs when sensors, actuators, and controllers exchange data packet across the communication network. Networked induced delay arises from sensor to controller and controller to actuator. This paper presents an adaptive delay compensation process for efficient control. Though Smith predictor has been commonly used as dead time compensators, it is not adaptive to match with the stochastic behavior of network characteristics. Time delay adaptive compensation gives an effective control to solve dead time, and creates a virtual environment using the plant model and computed delay which is used to compensate the effect of delay. This approach is simulated using TrueTime simulator that is a Matlab Simulink based simulator facilitates co-simulation of controller task execution in real-time kernels, network transmissions and continuous plant dynamics for NCS. The simulation result is analyzed, and it is confirmed that this control provides good performance.

• International Commerce and Information Review
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• v.13 no.4
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• pp.229-249
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• 2011

The exchange rate change has been increased since the time when the floating exchange rate system was introduced in Korea. As a result, the increase of the exchange rate changes raised the risk in international trades in Korea. Also after Bretton Woods System broke down, the increasing exchange rate fluctuation raised the risk in international trade. The purpose of this dissertation is to study whether this incomplete pass-through exists in Korean export industry and furthermore to measure the markup rate of the export price using real data since Global Financial Crisis. The estimation results of the export price determination model by Error Correction Model shows that the export price of Korea has been greatly influenced by the export prices and exchange rates against U.S. Dollar of rival countries, domestic producer price as well as the Korean Won-U.S. Dollar exchange rate and also business coincidence index of U.S. in demand. Particularly, the pass-through rate of Korean Won-U.S. Dollar exchange rate to export price is estimated to be incomplete, which contrasts with the propositions of traditional exchange rate determination approach, e. g. elasticity approach, monetary approach, etc.