• Journal of The Korean Association For Science Education
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• v.38 no.3
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• pp.407-417
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• 2018

The purpose of this study is to analyze the roles of classroom activities in science lessons and student learning motivation in achieving students' scientific competencies, and to suggest implications for science lessons to develop scientific competencies. For this, based on the PISA 2015 data of Korean high school students, we analyzed how classroom activities in science influenced students' scientific competencies through learning motivation variables. As a result of the path analysis, the activities emphasizing interaction and a link to real life predicted intrinsic motivation, instrumental motivation, and science efficacy significantly. On the other hand, the activities that emphasize the student-led inquiry process did not show any effect on learning motivation. In addition, the higher the motivation to learn the science, the higher their scores in three scientific competencies: explaining phenomenon scientifically, evaluating and designing scientific inquiry, and interpreting data and evidence scientifically. The practices of school science lessons indirectly influenced the achievement of scientific competence through learning motivation. Specifically, the activities emphasizing interaction influenced achieving scientific competencies through intrinsic motivation, and the activities emphasizing linkage to real life influenced it through all learning motivation variables. Finally, we discussed some implications for the roles and practices of school science class for enhancing students' scientific competencies.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.55-68
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• 1999

Many ITS services require map databases in digital form to meet desired needs. Due to the dynamic nature of ITS and the sheer diversity of applications, the design and development of spatial databases to meet those needs pose a major challenge to both the public and private sectors. This challenge is further complicated by the necessity to transfer locationally referenced information between different kinds of databases and spatial data handling systems so that ITS products will work seamlessly across the region and nation. The Purpose of this paper is to develop the framework-models commonly to reference locations in the various applications and systems-the ITS Map Datum and LRS(Location Referencing System). The ITS Map Datum consists of the around control points which are the prime intersections (nodes) of the nationwide road network In this study, the major points have been determined along wish link-node modeling procedure. LRS, defined as a system for determining the position (location) of an entity relative to other entities or to some external frame of reference, has also been set up using CSOM type method. The method has been implemented using ArcView GIS software over the Kangnam and Seocho districts in the city of Seoul, showing that the implemented LRS scheme can be used successfully elsewhere. With the proper advent of the K.ITS architecture and services, the procedure can be used to improve the data sharing and to inter operate among systems, enhancing the efficiency both in terms of money and time.

• Journal of Korea Multimedia Society
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• v.8 no.7
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• pp.924-942
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• 2005

Recently, large-scale directories have been developed for LINUX cluster file systems to store and retrieve huge amount of data. One of them, GFS directory, has attracted much attention because it is based on extendible hashing, one of dynamic hashing techniques, to support fast access to files. One distinctive feature of the GFS directory is the flat structure where all the leaf nodes are located at the same level of the tree. Hut one disadvantage of the mode structure is that the height of the mode tree has to be increased to make the tree flat after a byte is inserted to a full tree which cannot accommodate it. Thus, one byte addition makes the height of the whole mode tree grow, and each data block of the new tree needs one more link access than the old one. Another dynamic hashing technique which can be used for directories is linear hashing and a couple of researches have shown that it can get better performance at file access times than extendible hashing. [n this research, we have designed and implemented an extendible hashing directory and a linear hashing directory for large-scale LINUX cluster file systems and have compared performance between them. We have used the semi-flat structure which is known to have better access performance than the flat structure. According to the results of the performance evaluation, the linear hashing directory has shown slightly better performance at file inserts and accesses in most cases, whereas the extendible hashing directory is somewhat better at space utilization.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.282-292
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• 2003

This paper proposes an efficient data structure for forwarding IPv4 and IPv6 packets at the gigabit speed in backbone routers. The LPM(Longest Prefix Matching) search becomes a bottleneck of routers' performance since the LPM complexity grows in proportion to the forwarding table size and the address length. To speed up the forwarding process, this paper introduces a data structure named BMT(Bit-Map Tie) to minimize the frequent main memory accesses. All the necessary search computations in BMT are done over a small index table stored at cache. To build the small index table from the tie representation of the forwarding table, BMT represents a link pointer to the child node and a node pointer to the corresponding entry in the forwarding table with one bit respectively. To improve the poor performance of the conventional tries when their height becomes higher due to the increase of the address length, BMT adopts a binary search algorithm for determining the appropriate level of tries to start. The simulation experiments show that BMT compacts the IPv4 backbone routers' forwarding table into a small one less than 512-kbyte and achieves the average speed of 250ns/packet on Pentium II processors, which is almost the same performance as the fastest conventional lookup algorithms.

• Journal of Broadcast Engineering
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• v.12 no.2
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• pp.80-92
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• 2007

IPTV Services that is representative union service of broadcasting and telecommunication need guarantee of QoS, efficiency of multicasting, and hish bandwidth on the network. Because typical TDM based metro transport network was designed by transporting fixed voice traffic with stable and recovering method, it has a defect of bottleneck and a waste of bandwidth for acceptance of data traffic with burst feature and then all of data are treated equally at the transport network because it cannot classify between advanced high end service and best effort low end service. for completely resolving this kind of problem about increasing burst traffic and QoS issues, firstly we need to new design for transport network. This paper presents transformation method from TDM based metro transport network to packet based transport network and advantage and effectiveness of packet based transport network and also indicates technical factor and characters about method of packet transport system. As a result of research, the Packet Transport System, which is a transmission network for packet delivery, take in not only a specific character of legacy TDM but QoS, Multicast and high bandwidth, then, it is able to keep an effective bandwidth and a stabilized performance of packet transmissions. Additionally, if a fault be occurred on an optical link, the system is able to guarantee a differential QoS by an each service class using an algorithm to make certain of a traffic existence and contain a protective mechanism.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6805-6810
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• 2014

Background: Previous studies have suggested a link between obesity and breast cancer (BC). However, there is no universal consensus, especially in population based studies. Because only few studies have been conducted on African women, we aimed here to assess the relationship between BMI at time of diagnosis and the BC histopathological features among Tunisian patients according to menopausal status using a hospital-based prospective cohort study. Materials and Methods: Clinical and pathological data were collected from 262 patients stratified on four groups according to their BMI. The relationship between BMI and histopathological features at diagnosis was analysed using univariate and multivariate analysis. Receiver-operating characteristic (ROC) curves were used to evaluate the performance of BMI in predicting of high tumor grade, in comparison to ki-67 index of proliferation. Results: Obesity was correlated with larger tumors, advanced grade and with ER-PR-Her2+ BC subtype. An association of BMI with tumor size and tumor grade was observed in both premenopausal and postmenopausal women. Additionally, a significant association between BMI and ER+, ER+PR+Her2+ and ER-PR-Her2+ status was revealed for premenopausal patients, while only ER+PR+Her2+ was associated with BMI for postmenopausal women. Finally, our results showed that compared to Ki67 proliferation index, BMI is a useful prognostic marker of high grade BC tumors. Conclusions: These data are the first to show that in Tunisia obese women suffering from BC have significantly larger tumors and advanced tumor grade and that higher BMI might influence tumor characteristics and behavior.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.41-47
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• 2007

The first geostationary satellite made by Korea, COMS, has the three different payload ; Meteorological sensor, Oceanographic sensor and Ka-band communication payload. There are Meteorological & Ocean Data Communication Subsystem(MODCS) and Telemetry, Command and Ranging Subsystem(TC&R) as other RF radiation sources. MODCS transmits and receives Meteo and Ocean measurement data from/to earth using L-band and TC&R using S-band. The Ka-band communication payload will provide high-speed multimedia services and communication services for natural disaster such as prediction, prevention, and recovery services in the government communications network.Ka-band beacon is for the earth antenna pointing and the experiment of rain fading. This paper gives the analysis results about the mutual radiation effect on Ka-band communication payload, Ka-band beacon, MODCS and TC&R. Up/Down link power and coupling factor including the geometrical position and distance of antenna, filter rejection and degradation factor due to the different polarization are considered. The results show MODCS and TC&R are compatible for Ka-band communication payload and Ka-band beacon does not interfere with MODCS and TC&R normal operation.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.76-84
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• 2013

In the passive emitter localization using instantaneous TDOA (time difference of arrival) and FDOA (frequency difference of arrival) measurements, the estimation accuracy can be improved by collecting additional measurements. To achieve this goal, it is required to increase the number of the sensors. However, in electronic warfare environment, a large number of sensors cause the loss of military strength due to high probability of intercept. Also, the additional processes should be considered such as the data link and the clock synchronization between the sensors. Hence, in this paper, the passive localization of a stationary emitter is presented by using the successive TDOA and FDOA measurements from two moving sensors. In this case, since an independent pair of sensors is added in the data set at every instant of measurement, each pair of sensors does not share the common reference sensor. Therefore, the QCLS (quadratic correction least squares) methods cannot be applied, in which all pairs of sensor should include the common reference sensor. For this reason, a Gauss-Newton algorithm is adopted to solve the non-linear least square problem. In addition, to show the performance of the proposed method, we compare the RMSE (root mean square error) of the estimates with CRLB (Cramer-Rao lower bound) and derived the CEP (circular error probable) planes to analyze the expected estimation performance on the 2-dimensional space.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.93-98
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• 2004

Serial ATA interface Is inexpensive comparatively and performance is superior. So it is suitable technology in demand that now require data transmission and throughput of high speed. This paper describes a design and implementation of Serial ATA Link layer about error detection and 8b/10b encoder/decoder for DC balance in frequency 150MHz. The 8b/10b Encoder is partitioned into a 5b/6b plus a 3b/4b coder. The logical model of the block is described by using Verilog HDL at register transistor level and the verified HDL is synthesized using standard cell libraries. And it is fabricated with $0.35{\mu}m$ Standard CMOS Cell library and the chip size is about $1500{\mu}m\;*\;1500{\mu}m$. The function of this chip has been verified and tested using testboard with FPGA equipment and IDEC ATS2 test equipment. It is used to frequency of 100MHz in verification processes and supply voltage 3.3V. The result of testing is well on the system clock 100MHz. The designed and verified each blocks may be used IP in the field of high speed serial data communication.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.1
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• pp.47-62
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• 2012

To propagate clinical disease management service, there should be built a ecosystem where service developers, service providers, device suppliers closely cooperate for u-Health platform. However, most u-Health platform is difficult to build an effective ecosystem due to the lack of secure and effective PHR(Personal Health Record) management, the lack of personalized and intelligent service, difficulties of N-screen service. To solve these problems we suggest the CDMP(Chronic Disease Management Platform) architecture. The CDMP is a software platform that provides the core functions to develop the chronic disease management services and performs a hub function for the link and integration rbetween various services and systems. CDMP is SOA based platform that enables a provision of reusability, expansibility and it provides open API where everybody can share information, contents and services easily. CDMP supports the multi platform system foN-screen service and the self management functions via SNS. In this paper, we design and implement the CDMP including PHR service based on hybrid data model for privacy preservation. Experiment results prove the effectiveness of hybrid model-based PHR service.