• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.281-288
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• 2005

It is generally accepted that self-similar (or fractal) Processes may provide better models for teletraffic in modem computer networks than Poisson processes. f this is not taken into account, it can lead to inaccurate conclusions about performance of computer networks. Thus, an important requirement for conducting simulation studies of telecommunication networks is the ability to generate long synthetic stochastic self-similar sequences. A generator of pseudo-random self similar sequences, based on the SRA (successive random addition) method, is implemented and analysed in this paper. Properties of this generator were experimentally studied in the sense of its statistical accuracy and the time required to produce sequences of a given (long) length. This generator shows acceptable level of accuracy of the output data (in the sense of relative accuracy of the Hurst parameter) and is fast. The theoretical algorithmic complexity is O(n).

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.469-472
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• 2008

In this paper, we discuss the recent trends on the passive UHF RFID tag chip design techniques and several important system parameters. We also summarize link budget studies on both conventional and modem UHF RFID communications. The paper highlights the reverse link limited case, which has known to be the minor concern if reader continuous wave (CW) can reach the tag in sufficient level. This makes sense when the tag sensitivity is rather high (over 10-12${\mu}W$); however, since the tag chip fabrication technologies have been developed by time, the tag chip threshold levels are now less-dominant in determining link margin. If the tag limitation can be alleviated, the forward link limited case can be resolved; thus, we rather focus on the path-loss problem. Since the path-losses are still exist in both forward and reverse links, and it can be doubled while CW travels the reader-tag-reader path because forward link and reverse link are on the same distance. Consider if reader receiver sensitivity is very high in the worst case. In this case, weaken tag response (i.e., backscatters) cannot reach the level that reader receiver can process tag data; bit-error rate can be higher. Overall, backscatter levels should be high enough so that reader receiver can correctly function. After discussing link budget, we carried out practical measurements on fading effects between two circularly polarized UHF RFID antennas in a small scale area.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.477-480
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• 2006

To represent the accurate feature of signal and system, many researches have been done in many fields of basic and engineering science which led a great development of modem society. Even until currently, in order to acquire useful information from signals at high speed, many methods and transforms have been processed. In these methods, the Fourier transform which represents signal as the combination of the frequency component has been applied to the most fields. But as transform not to consider time information, the Fourier transform does not provide time information of the time and presents only overall features of signals. The wavelet transform, which is proposed to overcome this problem and recently expands the range of the application, presents time-frequency localization and many kinds of the wavelet can be applied according to the environment of application. In this paper, we detect the features of signals using the function which is considered as the wavelet and do research for filtering locally in the wavelet plane.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.431-436
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• 2003

It's about time we had to think an alternative to recover out insufficient fishery market caused by IMF locally as well as the fishery agreement on Japan and China. The Ministry of Maritime Affairs ＆ Fisheries have planning the advancing fishery information integrated system for the fishing present condition, marine resource administration and applicability consideration. The fishery information communication system is build up to the raw data ＆ process-network-content. The communication system must be small size, low cost and adapted SSB transceiver, that is using fishery shipping. In this paper We present digital data communication network to exchange information for fishery and safety between fishing ship and coast station in cheeper communication fee using SSB(single Side Band) in HF(High Frequency) band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2097-2104
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• 2009

In terrestrial communications, high data rate transmission can be achieved by splitting the coverage area into small cells through base stations and reusing the resource efficiently. However, the geographical features of maritime communications require the long transmission range, and it is not practical to install base station on the sea to set up the similar deployment as the terrestrial communications, so MF/HF band modem with low data rate are currently utilized for maritime communications. And the expensive satellite communication via Inmarsat is the conventional solution for the high data rate transmission on the sea. To reduce the cost, Ad-hoc network is proposed to apply on the sea, which requires no base station for the peer-to-peer communications. In this paper, we denominate this maritime environment specific Ad-hoc network as Nautical Ad-hoc Network (NANET). Furthermore, the deployment scenario for the NANET, and the analysis on multiple access and duplexing schemes for the NANET are discussed in this paper, which serves as the cornerstone for the further NANET research and development.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1597-1603
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• 2017

The incidence of fire in underground utility tunnel is lower than other fires, but the damage caused by fire can cause social loss due to social management paralysis as well as economic loss. Hereupon, this paper presents the results of an empirical test on the construction of the underground utility tunnel condition monitoring system using the leakage coaxial cable installed in the underground utility tunnel. For this reason, a verification test was conducted by connecting a inductive coupler 200 Mbps power line communication modem with insertion loss characteristics of $-6{\pm}2dB$ to the installed the leakage coaxial cable installed in the underground utility tunnel. As a result, We confirmed sending/receiving of IP cameras up to 500 m. Therefore, it is judged that it is possible to construct a condition monitoring system for underground utility tunnel by using the leakage coaxial cables installed in the underground utility tunnels without installing additional communication lines for data transmission.

• Journal of the Korean Society for Library and Information Science
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• v.22
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• pp.259-304
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• 1992

This paper examines 'Religion Class' in the scheme of the DDC. The major findings of the study are summerized as follows. 1. The first edition of DDC was published in 1876 in order to classify Amherst College Library collections. In spite of the continuous study and revision of the experts, the frameworks of the DDC systems are still kept unchanged. Only their subdivisions, reflecting those developments in the academic world, are developed and detailed more sophisticatedly. 2. The division of 200 does not function as generalities for all class of religion. Therefore, it is necessary to amend the division of 200 to serve generalities for all the religions of the world. 3. Standard subdivision for the christian religion and for the non-christian religion is different. So, the mnemonic nature has become weakened due to the dual standard subdivisions and the classification number becomes much longer and complicated. Therefore, one standard subdivision for all religions of the world is required. 4. Religion science was organized in late 19 C and developed continuously, but the DDC does not accomodate the religion science as a science. Accodingly, the DDC should be revised recognize religion science as a science not the christian science. 5. The deployment of classification scheme in Dewey's 200 is severely biased. That is to say, 9 division were assigned for christian religion, whereas only 1 division was assigned for non-christian religion. Therefore, an adjustment should be made to allocate subdivisions equally to all religions of the world. 6. General classification order of religion is prehistoric, primitive, ancient, modem and world religion in religion science. But, DDC does not accept this general classification order of religion, sticking to the biased expansion towards christianity. Therefore, DDC must adopt the general classification order of religion in the religion science. 7. Lastly, because of the limitation of decimal notation in DC, DDC does not accomodate new subject equally and classification number becomes longer. Therefore, centesimal expansion is proposed in order to make the classification number short, to enlarge its capacity of inclusion of new subject and to maintain consistency in the scheme.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.2
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• pp.66-74
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• 2008

Since modem embedded systems need to access, manipulate or store sensitive information, it requires being equipped with cryptographic file systems. However, cryptographic file systems result in poor performance so that they have not been widely adapted to embedded systems. Most cryptographic file systems degrade the performance unnecessarily because of system architecture. This paper proposes ISEA (Indexed and Separated Encryption Approach) that supports for encryption/decryption in system architecture and removes redundant performance loss. ISEA carries out encryption and decryption at different layers according to page cache layer. Encryption is carried out at lower layer than page cache layer while decryption at upper layer. ISEA stores the decrypted data in page cache so that it can be reused in followed I/O request without decryption. ISEA provides page-indexing which divides page cache into cipher blocks and manages it by a block. It decrypts pages partially so that it can eliminate unnecessary decryption. In synthesized experiment of read/write with various cache hit rates, it gives results suggesting that ISEA has improved the performance of encryption file system efficiently.

• Journal of Korean Medical classics
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• v.21 no.1
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• pp.43-62
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• 2008

After parturition, woman in childbed's health can grow worse. Because when woman in childbed gives birth, Genital organ can be damaged, and lost a lot of blood, and also consume a lot of physical strengths. So, after parturition, woman in childbed is easy to fall in disease if do not take care in health specially. So after parturition, woman in childbed should be careful in stress, sleep, food etc. This thesis described Postpartum Spasm[痙病], Oppressive Feeling and Dizziness[鬱冒], Constipation[便秘], Abdominal Pain[腹痛], Diarrhea[下利], Annoyance[煩亂] and Vomitting Sickness[嘔逆]. Postpartum Spasm[痙病]'s major symptom is rigided body. This disease corresponds to Tetanus in modem medicine, and bacterial infection is assumed for cause. By Oriental medicine, after parturition, when blood is lacking, if patient takes wind, this disease breaks out. Oppressive Feeling and Dizziness[鬱冒]'s major symptom is dizzy head and gloomy eye. After parturition, when blood is lacking, if patient sweats too much and take cold, this disease breaks out. After parturition, if patient consumes a lot of resins of human body, Constipation[使秘] breaks out. There are four causes to Abdominal pain[腹痛]. First, due to deficiency and cold treats by Danggwisaenggangyangyuktang(當歸牛薑羊肉湯). Second, due to stagnation of Gi(氣) treats by Jisiljakyaksan(枳實芍藥散). Third, due to blood stasis treats by Ha-eohyeoltang(下瘀血湯). Fourth, due to lochiorrhea treats by Daeseunggitang(大承氣湯). After parturition, Annoyance[煩亂] and Vomitting Sickness[嘔逆] due to fever of difficiency treat by Jukpidaehwan(竹皮大丸). After parturition, Febrile diarrhea[熱性下利] treats by Baekduonggagamchoagyotang(白頭翁加甘草阿膠湯). This disease is similar with present Bacillary Dysentery. After parturition, Exteroceptive disease due to taking wind treats by Yangdaltang. Due to wind and fever treats by Jukyeoptang(竹葉湯).

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.9-16
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• 2009

According to the construction of infrastructure for the water resource management services, the importance of the eco-friendly reservoir tank management is being spotlighted. In this paper, we proposed the eco-friendly reservoir tank management using prediction for improving the water quality and on-line managing efforts of reservoir tanks. The proposed method defined the context and environment of the reservoir tank and predicted the profited service according to the pump motion, the solar battery, the chemicals, the water level, the telephone line, and the modem using collaborative filtering. To evaluate the performance of the eco-friendly reservoir tank management system using prediction, we conducted sample T-tests so as to verify usefulness. This evaluation found that the difference of satisfaction by service was statistically meaningful, and showed high satisfaction. Accordingly, the satisfaction and the quality of services will be improved the efficient prediction by supporting the context information as well as the environment information.