• Journal of the Korea Society for Simulation
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• v.6 no.2
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• pp.117-124
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• 1997

A simulation model for the estimation of cutoff connection rate in the asynchronous transfer mode (ATM) switching system under multimedia traffic environments is presented. The simulator is developed by the integration of the AweSim tool with user-written C++ routines that model the internal structures of operational details of the switching system. For the case study, the simulator is applied to the ATM switching system developed by Electronics and Telecommunications Research Institute (ETRI) to compare design alternatives according to the cutoff connection rates.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.33.3-33
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• 2002

Pseudolite (PL) is a kind of signal generator, which transmits GPS-like signal at the ground. However our own made PL is different from a GPS satellite in clock accuracy. GPS satellites are synchronized by use of high precision atomic clocks. But because our PLs use low cost temperature controlled oscillators (TCXO), so it is very difficult to synchronize them. Hence, we should install reference station and use Differential GPS (DGPS) algorithm to calculate user position. By use of this method, we already developed indoor navigation system a few years ago. We named it as 'Asynchronous Pseudolite Indoor Navigation System'. However, this system requires that sampling times of all the receivers...

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.77-80
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• 2002

In this paper, we analyze a physical layer of W-CDMA .system and design a transmitter and receiver by using ADS (Advanced Design System). Also, we simulated a link level performance with different channel estimation algorithm in Jakes fading channel environment. For the channel estimator, we used the WMSA(Weighted Multi-Slot Averaging) algorithm, EGE(Equal Gain Estimation) algorithm and SSE(Symbol-to-Symbol Estimation) algorithm. This study will be useful in the analysis and design of W-CDMA system.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.102-105
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• 2003

"e-Leaning" system is classified by lecture time into two types, that is, "synchronous type" spent the same lecture time between the lecturer and students, and "asynchronous type" spent the different lecture time. The size of image database is huge, and there are some problem on the management of the lecture image database in "asynchronous type" e-Learning system. The one of them is that the time tag for the database management must be added manually at present, and the cost of the addition of the time tag causes a serious problem. To resolve the problem, we will use the character recognition for the characters written by the lecturer on whiteboard, and will add the recognized character as a keyword to the tag of the image database. If the database would have the keyword, we could retrieve the database by the keyword efficiently, and the student could select the interested lecture scene only in the full lecture database.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.3
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• pp.289-300
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• 2003

Traditional kernel-level communication systems for clusters are dependent upon computing platforms. Futhermore, they are not easy to use and do not provide various functions for clusters. This paper presents an architecture and various implementation issues of a kernel-level communication system, KCCM(Kernel level Cluster Communication Module), for linux cluster. The KCCM provides asynchronous communication services as well as standard synchronous communication services using send and receive. The KCCM also automatically detects and recovers connection failures at runtime. This allows programmers to use KCCM when they build mission critical applications over TCP-based connection-oriented communication environments. Having developed using standard socket interfaces, it can be easily ported to various platforms. The experimental results show that the KCCM provides good performance for asynchronous communication patterns.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.257-262
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• 2000

Recently, though there are many REES(Remote Education Estimation Systems), they have some tied and complete testing method not considering for the student individual specification and characteristic. This paper proposes the education model of the distributed asynchronous communication method which making a test without me and place limits using web estimation system from problem bank database, and attach effective method could improve student achievement, quality of estimation later problem filtering using user profile in order to consider the student individual difference and characteristic that not considered pre-Remote Education Estimation Systems. This is a adaptive DAC method improving the pre-DAC method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.2
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• pp.120-126
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• 1988

In this paper the performance of the asynchronous Repeated FH/MFSK system for the CDMA(Code Division Multiple Access) was analyzed. Actually there was no difference in the probabilities of hit of frequency between Random Coding method and frequency hopping pattern vector suggested by Einarsso. Actual situation was adopted as a model in thie simulation, on the assumption thet;a:there was no Noise, Multipath propagation, b:there was only mutual interference. c:the number of users M was given. Also it was found that there is almost no deviation between the value calculated from the formula of word error probability expressed by bound and that obtained from this simulation.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.512-517
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• 1998

In a matrix converter, input side and output side are coupled with each other through switching elements. Since disturbances on either side affect directly on the other side, it requires a high-speed on-line control system to compensate them. We proposed in previous papers a new control strategy and an on-line control circuit for a matrix converter. The control circuit could keep the output voltage at commanded value against fluctuation in the supply voltage. Furthermore wave forms of the output voltage and the input current were always kept sinusoidal. The switching pattern was generated by comparing modified voltage references with a carrier. The carrier was synchronized with the supply voltage using a PLL system, which made the control circuit complicated and costly. This paper discusses on the possibility of an asynchronized carrier. Experiment results show the input current distortion in case of asynchronous carrier is bigger than that of synchronous carrier. However, the deterioration can be minimized by increased carrier frequency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.559-575
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• 2023

3D human pose estimation is widely applied in various fields, including action recognition, sports analysis, and human-computer interaction. 3D human pose estimation has achieved significant progress with the introduction of convolutional neural network (CNN). Recently, several researches have proposed the use of multiview approaches to avoid occlusions in single-view approaches. However, as the number of cameras increases, a 3D pose estimation system relying on a CNN may lack in computational resources. In addition, when a single host system uses multiple cameras, the data transition speed becomes inadequate owing to bandwidth limitations. To address this problem, we propose a distributed real-time 3D pose estimation framework based on asynchronous multiple cameras. The proposed framework comprises a central server and multiple edge devices. Each multiple-edge device estimates a 2D human pose from its view and sendsit to the central server. Subsequently, the central server synchronizes the received 2D human pose data based on the timestamps. Finally, the central server reconstructs a 3D human pose using geometrical triangulation. We demonstrate that the proposed framework increases the percentage of detected joints and successfully estimates 3D human poses in real-time.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.5
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• pp.18-29
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• 2007

The main objective of this paper is to propose a new stability analysis method for a networked control system with multiple packet transmission. The new scheduling method that can guarantee the maximum time delay and discrete switch state equation model which represent a network data loss is proposed. The equivalent model of a MIMO(multi-input multi-output) networked control system is derived from a state space model of linear time invariant interconnected systems in the form of asynchronous dynamical system. Using this model, this paper presents new stability theorems that can determine stability of the networked control system with regard to time delay, data loss, and the number of transmission packets. Simulation results verify the effectiveness of proposed stability analysis method.