• 한국경영과학회지
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• 제27권3호
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• pp.59-74
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• 2002

This study investigates two basic operations of mobility management of PCNs (Personal Communication Networks), i.e., the location update and the paging of the mobile terminal. From the realistic consideration that a user either moves through several cells consecutively or stays in a cell with long time, we model the mobility pattern by introducing two types of CRT (Cell Residence Time). Mobility patterns of the mobile terminal are classified Into various ways by using the ratios of two types of CRT. Cost analysis is performed for distance-based and movement-based location update schemes combined with blanket polling paging and selective paging scheme. It is demonstrated that in a certain condition of mobility pattern and call arrival pattern, 2-state CRT model produces different optimal threshold and so, is more effective than IID ( Independently-Identically-Distributed) CRT model. An analytical model for the new CRT model is compact and easily extendable to the other location update schemes.

• Animal cells and systems
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• 제9권2호
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• pp.47-55
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• 2005

Avian vocalization has been main topics in studying animal communication. The structure and usage as well as development and function of vocalization vary enormously among species and even among populations, and thus we reviewed the general patterns of song learning and the consequences of song communication in birds at the behavioural level: first, we compared the different learning phenomena between non-songbird and songbird, and we investigated the learning process of songbird both in the field and in the lab, which are needed to fully understand vocal communication. Second, we discussed a recent trend of sexual selection hypothesis explaining the structural and functional diversity of song in songbirds with repertoire and presented how the repertoire is actually used between neighbours based on individual recognition.

• 영어어문교육
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• 제3호
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• pp.1-12
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• 1997

Errors in EFL writing are very often attributable to learner's inadequate understanding of the target culture. Most of these errors are very hard to identify because they are grammatically correct notwithstanding the meaning. EFL learners almost habitually equate the meaning and usage of a linguistic item when it is present both in the native and the target languages. However, seemingly identical items in both languages sometimes prove themselves to be distinct from each other because of cultural differences. Some expressions in the native language are neither socially acceptable nor meaningful in the target language. Out of sheer ignorance, moreover, one puts a target item in the way he may use it in his native language. For instance. the primary feature of the term "friend" in Korean is [+same age group]. So, a Korean young man is not supposed to call his teacher a friend. This paper aims to clarify patterns of college level writing errors caused by interference of mother culture.

• Transactions on Control, Automation and Systems Engineering
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• 제2권2호
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• pp.121-129
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• 2000

In this paper, an optimal group control for elevator systems is proposed with timed Petri net based approach. Elevator system is modeled by time Petri nets and hall call response times are estimated with moment generating functions (MGFs) methos, which is applicable to real traffic patterns. Two assignment policies are proposed to satisfy the demands of passengers(i.e. hall/car calls) and to handle exceptional situations. In addition, optimal algorithms are implementated to minimize cost functions. THe performances of the elevator system employing the proposed algorithms are compared with each others in ways of several performance measures by a computer simulation.

• 한국문헌정보학회지
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• 제3권
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• pp.1-24
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• 1973

This paper is intended as a basic study in which the purpose is to provide understanding of the workings of man in relation to his information resources. Such understanding would prove of value in formulating the policies of an inoformation center serving the fields of science and technology. The information problem of the scientific community was assessed in the lights of the characteristics of the information (cumulativeness, currency versus obsolescence, volume versus redundancy, interrelationships, and foreign literature)and the flow of information and communication patterns covering the use of the variety of media and the information gathering habits of scientists. What can be done to ease the problem was sought in the improvements and innovations which call the attentions of the scientists and the technologists as producers and users of the information, of the professional organizations of various disciplines and of government.

• East Asian mathematical journal
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• 제26권4호
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• pp.447-461
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• 2010

Papert [17] introduced the LOGO environment in which we make a curve using LOGO commands (FORWARD, ROTATE). We call this geometry as turtle geometry. This environment has influenced many researchers and designers of computers and mathematics education. But the curve that we can make using LOGO command is elementary or too difficult. Polygon and circle is elementary and making other curves is difficult. In this paper, we introduce the method of drawing some other curves mediating new command. First, we study epicycloid and hypocycloid in the historical and the physical context. And we introduce the method of making epicycloid and hypocycloid using vector addition. Next we study the polygon patterns of this curve. Finally, we extend the method for making more general curve and we improve the computer environment using this metaphor.

• 대한산업공학회지
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• 제28권4호
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• pp.425-434
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• 2002

Mobility of service users makes location update and paging (L/P) procedures indispensable features in mobile communication networks. Importance of optimizing the configuration of L/P areas has been increased by the growth of L/P related signaling. In this study, we deal with the L/P configuration which an LA (Location Area) may contain multiple PAs (Paging Areas). Given the network topology, L/P related parameters, and traffics generated by each cell, is provided the problem of finding optimal LA/PA configuration minimizing the amount of L/P related signaling. The optimization problem is solved using a simulated annealing, and detailed computational results are conducted to capture the effects of mobility, call arrival patterns and boundary crossing rate on the LA and PA configurations.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.1029-1032
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• 2000

A neuro-fuzzy based circuit to recognize circuit pat-terns is proposed in this paper. The simple algorithm and exemption from the use of template patterns as well as multipliers enable the proposed circuit to implement on the hardware of an economical scale. Furthermore, thanks to the circuit design by using current-mode techniques, the proposed circuit call achieve easy extendability of tile circuit and efficient pattern recognition with high-speed. The validity of the proposed algorithm and tile circuit design is confirmed by computer simulations. The proposed pattern recognition circuit is integrable by a standard CMOS technology.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.902-905
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• 2000

Because of the rapid growth of Internet and multimedia applications, how to protect IPR (intellectual property rights) has become a critical issue. Is one of the ways to overcome the problem of the protection of IPR. Digital watermarking call be applied to multimedia data, such as digital images, digital video, and digital audio. In this paper, we propose a digital watermarking technique for digital images to authenticate an owner or an image by embedding visually recognizable patterns, such as logos, signatures, or stamps into images In BDCT (block discrete cosine transform) frequency domain. The proposed method sorts the components of an original image twice. At the same time, the method, also, rearranges the components of a watermark twice in order to be more robust, and finally embeds the watermark into the image. From the experimental results, the conjunction of three similarity measurements shows that our proposed method is robust to image cropping, image filtering, and JPEG (the Joint Photographic Experts Group) both subjectively and objectively.

• 기본간호학회지
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• 제6권1호
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• pp.51-63
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• 1999

This study examined two differences in physical and psychological recovery patterns after surgery in the elderly. The sample consisted of 40 patients with abdominal surgery In five large hospitals in Seoul. The data for this study were collected from Apr. 20 to Nov. 26 by structured questionnaire, chart review and call. Physical recovery was assessed by ADL, a Cantril Ladder Scale and a Visual Analogue Scale. Psychological recovery was measured by the Geriatric depression Scale and a Cantril Ladder Scale. The data were analyzed using frequency, percentage, Pearson Correlation Coefficient, and MANOVA by SPSS/WIN. The result are as follows : 1. Physical recovery indicated significant improvement over time with the exception of ADL(F=.812 p=.449). Perceived physical health were significantly improved(F=6.189 p=.004). Pain & discomfort was significantly decreased(F=3.927 p=.025). 2. Perceived psychological health was significantly improved over time(F=20.648 p=.000), but depression showed no statistical significance improvement over time(F=1.393 p=.256). 3. There were no significant effects of sex, age, complication and combined chronic diseases on physical and psychological recovery patterns. 4. There were significant correlations between operation time and pain(r=-.331 p=.020), recovery time and perceived psychological health(r=-.320 p=.024), recovery time and pain(r=.404 p=.005). There were significant correlations between admision period and ADL(r=-.418 p=.004), perceived physical health(r=-.354 p=.014), depression(r=.280 p=.042), and perceived psychological health(r=-.447 p=.002). BRAS showed significant correlation with ADL(r=-.458 p=.002). 5. With an increase in the degree of perceived health(physical and psychological), ADL was significantly increased. With an increased in the degree of depression and pain, ADL and perceived health(physical and psychological) were significantly decreased. In conclusion, the elderly patient recovered significantly over time with the exception of ADL and depression. It these we suggested to considered when planning care for elderly patients.