• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.8
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• pp.9-16
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• 2007

Currently, the measurement of RF parameters for a base station in operation is typically limited to easily measured forward path items. In this paper, the forward monitoring ports of base stations are used to measure the reverse RF performance. The system has been implemented and effectiveness has been proven on an operating base station. The receiver sensitivity is measured using an internal CDMA modem which is used to monitor the output power based on closed loop power control when the modem is connected to the base station via a voice call. In order to improve accuracy, in addition to the modem Tx adjust(TxAdj) parameter, the detector's actual measurement is used. For accurate receiver sensitivity, the measurement should be made when there is no traffic which is not possible on an operating base station. Therefore, pilot channel chip energy to received signal power spectral density ratio$(E_c/I_o)$ compensation method is used to offset the receiver sensitivity degradation with voice traffic increase.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.377-380
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• 2010

MANET(Mobile Ad-hoc Network) has been proposed as a infrastructure-less network using distributed algorithm for remote environment monitoring and control. The mobility of MANET would make the topology change frequently compared with a static network and a node is resource-constrained. Hence, to improve the routing protocol in MANET, energy efficient routing protocol is required as well as considering the mobility would be needed. In this paper, we extend RODMRP(Resilient Ontology-based Dynamic Multicast Routing Protocol) structure by a modifying the level of cluster. We call this network protocol CACH-RODMRP. Our contribution consists estimating the optimal level of clustering depth with considering node position and reducing the network residual energy. The simulation results of proposal algorithm show that the energy is significantly reduced compared with the previous clustering based routing algorithm for the MANET.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.509-516
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• 2004

The measurement of abnormal change of temperature(temperature anomaly) will help determine the safety of various engineering constructions, as the measurement in body often used to diagnose one's health. Temperature anomaly can be occurred in leakage or seepage of water flow in rocks, and in ground water table etc. Grouting materials injected in fractured rocks generate heat during hardening process. The degree of temperature change is associated directly with heat flow characteristics, that is, thermal conductivity, specific heat capacity. density of the surrounding rocks and can afford to assess the grouting efficiency. However, in practice, the use of traditional temperature measuring technique composed of only one single thermal sensor has been fundamentally limited to acquire thermal data sufficient to use for that, partly due to the time-consuming measuring work, partly due to the non-consecutive quality of data. Thus, in this paper, a new concept of temperature measuring technique, what we call, thermal line sensor technique is introduced. In this, the sensors with an accuracy of $0.02^{\circ}$ are inserted at regular intervals in one line cable and addressed by a control device, which enables to fundamentally enhance the capability of data acquisition in time and space. This new technology has been demonstrated on diverse field model experiments. The results were simply meant to be illustrative of a potential to be used for various kinds of temperature measurements encountered in grouting and leakage problems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4B
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• pp.444-454
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• 2004

To support diverse transmission requirements of multimedia applications, Quality of Service (QoS) should be provided in the Internet, where only the best-effort service is available. In this paper, we describe our recent effort on the implementation and verification of an extendable and flexible QoS allocation and resource management system based on the bandwidth broker model for realizing the IETF differentiated service (DiffServ). Focusing on the bandwidth issue over single administrative domain, the implemented system provides real-time resource reservation and allocation, delayed call admission control, simple QoS negotiation between sewer and users, and simple resource monitoring. The implemented system is verified by evaluating the performance of a resource-intensive application over the real-world testbed network.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.2
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• pp.24-30
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• 2009

In this paper, the FPGA modem platform complying with 3GPP Release 7 eHSPA specifications and its regularized verification flow are proposed. The FFGA platform consists of modem board supporting physical layer requirements, MCU and DSP core embedded control board to drive the modem board, and peripheral boards for RF interfacing and various equipment interfaces. On the other hand, the proposed verification flow has been regularized into three categories according to the correlation degrees of hardware-software inter-operation, such as simple function test, scenario test call processing and system-level performance test. When it comes to real implementations, the emulation verification strategy for low power mobile SoC is also introduced.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.826-831
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• 1988

This paper presents an approach to segment an image into areas of surfaces, and to compute the surface properties from a gray-scale image in order to describe the surfaces for reconstruction of the 3-D shape of the objects. In general, an rigid body has several surfaces and many edges. But if it is not polyhedoron, it is necessary not only to describe the relation between surfaces, i.e. its line drawings but also to represent the surfaces' equations itself. In order to compute the surfaces' equation we use a probability of edge distribution. At first it is extracted edges from a gray-level image as much as possible. These are not only the points that maximize the change of an image intensuty but candidates which can be seemed to be edges. Next, other character of a surface (color, coordinates and image intensity) are extracted. In our study, we call the all feature of a surface as "texture", for example color, intensity level, orientation of an edge, shape of a surface and so on. These features of a surface on a pixel of an image plane are mapped to a point of the feature space, and segmented to each groups by cluster analysis on this space. These groups are considered to represent object surface in an image plane. Finally, the states of object surface in 3-D space are computed from distributional probability of local and overall statistical features of a surface, and from shape of a surface.a surface.

• Journal of Korean society of Dental Hygiene
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• v.7 no.1
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• pp.61-72
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• 2007

The purposes of this study were to investigate the oral health status of the disabled children attending special schools in Seoul and Gyeonggi area, which were to collect baseline data for set up a oral health center in special schools. The study group comprised 915 disabled children aged 12~15 year. They were examined clinically and surveyed on 4 oral health related characteristics according to the type and level of disabilities The results may be summarized as follows: 1. DMFT index was the highest in children with crippled disorder. The plaque control was more required to the children with mental retardation or developmental disorder other than another types of disabilities. 2. About one third of the children with mental retardation or developmental disorder had their teeth brushed at least 3 times daily without any help. Over the half of the children with crippled disorder had their teeth brushed 2 times daily, 33.3% were independent and 38.9% totally dependent on help from others. 3. The more level of disabilities was higher, the more frequency of tooth brushing was lower and degree of dependance of the tooth brushing was higher. 4. There was tendency to visit to dental office more frequently for relief of dental symptoms in children with crippled disorder 5. The inability to call for help from others was the major barrier to dental care for the disabled.

• Journal of Korea Spatial Information System Society
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• v.4 no.1 s.7
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• pp.5-14
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• 2002

The generalization of geospatial data is an important way in deriving a new database from an original one. The generalization of a geospatial object changes not only its geometric and aspatial attributes but also results in propagation to other objects along their relationship. We call it generalization propagation of geospatial databases. Without proper handling of the propagation, it brings about an inconsistent database or loss of semantics. Nevertheless, previous studies in the generalization have focused on the derivation of an object by isolating it from others. And they have proposed a set of generalization operators, which were intended to change the geometric and aspatial attributes of an object. In this paper we extend the definition of generalization operators to cover the propagation from an object to others. In order to capture the propagation, we discover a set of rules or constraints that must be taken into account during generalization procedure. Each generalization operator with constraints is expressed in relational algebra and it can be converted to SQL statements with ease. A prototype system was developed to verify the correctness of extended operators.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.6
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• pp.597-604
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• 2019

In this paper, we propose an improved method on an adaptive application of the CPP(Chinese Postman Problem) algorithm to the protocol test suite generation for conformance testing. Also, we present an example application of this CPP algorithm to B-ISDN Q.2931 call/connection control procedure for the purpose of showing how it can be adapted to generate a test suite for conformance testing of a communication protocol. The proposed method has an advantage of an optimization technique which finds a minimum cost of test suite from a standardized specification, so this optimization technique of the CPP algorithm can be practically applied to a real environment for testing a conformity of a protocol implementation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.9
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• pp.1730-1738
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• 1994

Broadband code division multiple access(B-CDMA)previously proposed for personal communication services(PCS) is not suitable for high-speed data services with large variations in speed, because it is designed only for low-speed voice calls with small variations in speed. Meanwhile, hybrid intra-cell TDMA/inter-cell CDMA(Hybrid TDMA/CDMA) recently proposed could accomodate high-speed services easily because of its internal use of the TDMA scheme, but there would be much inefficiency in treating variable bit rate services due to the intrinsic properties of TDMA transmission scheme, In this paper, a media access control(MAC) protocol, called Resevation TDMA/CDMA, which uses a reservation scheme similar to the one in the packet reservation multiple access(PRMA) protocol to compensate for these shortcomings is proposed. In addition, the performance of this protocol is analyzed and compared with conventional protocols by computer simulation. According to the simulation results, it has been shown that the proposed Reservation TDMA/CDMA scheme could support various transmission rates of user data traffics easily, and it could utilize the variations of the treansmission rates in each active call more efficiently.