• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.111-133
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• 2015

This study was carried out to survey the vascular plants of Baekdudaegan Arboretum area. The results are as follows. The numbers of flora in this study area were summarized as 655 taxa including 95 families, 332 genera, 567 species, 5 subspecies, 72 varieties and 11 formas. The rare plants were 17 taxa including Parasenecio firmus, Rhododendron micranthum, Iris odaesanensis, Lysimachia coreana and so forth. The Korean endemic plants were 16 taxa including Weigela subsessilis, Heloniopsis koreana, Salix koriyanagi, Vicia chosenensis and so forth. Plants Adaptable to Climate Change were Northern plants 18 species, Southern plants 2 species, endemic plants 10 species. The naturalized plants were 44 taxa and ratios of naturalized index and urbanization index were estimated Core area 10.2% and 4.9%, Mt. Munsu 4.9% and 2.3% and Mt. Okseok 5.5% and 2.6%. The floristic regional indicator plants found in this area were 3taxa(2.5%) of grade V, 12taxa(11.0%) of grade IV, 22taxa(20.2%) of grade III, 35taxa(32.1%) of grade II. In life forms, hemicryptophytes were The most dominant. Next was a Therophytes. In addition, 492 taxa were categorized by usage into 8 groups, as follows: Edible 239taxa(36.5%), Fiber 10taxa(1.5%), Industrial 1taxon(0.2%), Miscellaneous 183taxa(27.9%), Ornamental 65taxa(9.9%), Pasturing 259taxa(39.5%), Siscellaneousg 14taxa(2.1%) and Timer 21taxa(3.2%).

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.6
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• pp.57-65
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• 2007

This paper presents the design of single phase PFC(Power Factor Correction) using a DSP(TMS320F2812). In order to realize the proposed boost PFC converter in average current mode control, the DSP requires the A/D sampling values for a line input voltage, a inductor current, and the output voltage of the converter. Because of a FET switching noise, these sampling values contain a high frequency noise and switching ripple. The solution of A/D sampling keeps away from the switching point. Because the PWM duty is changed from 5% to 95%, we can#t decide a fixed sampling time. In this paper, the three A/D converters of the DSP are started using the prediction algorithm for the FET ON/OFF time at every sampling cycle(40 KHz). Implemented A/D sampling algorithm with only one timer of the DSP is very simple and gives the autostart of these A/D converters. From the experimental result, it was shown that the power factor was about 0.99 at wide input voltage, and the output ripple voltage was smaller than 5 Vpp at 80 Vdc output. Finally the parameters and gains of PI controllers are controlled by serial communication with Windows Xp based PC. Also it was shown that the implemented PFC converter can achieve the feasibility and the usefulness.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.197-203
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• 2011

This experiment was carried out to investigate the growth characteristics of virus-free sweetpotato in hydroponic bag culture. The rooted one-node and upper-shoot cuttings of 'Yeonhwangmi' and 'Mannamiwere' transplanted into the plastic bag (0.5 mm of thickness, $W300{\times}L1,200{\times}H120mm$) culture system filled with commercial horticultural media (TKS-2, Flora Gard Co.) and cocopeat + perlite (3 : 7, 5 : 5, 7 : 3, (v/v). Nutrient solution of National Horticultural Research Station in Japan was separately irrigated $3times{\times}30minutes$ per day (10:00, 14:00 and 20:00 with timer control) by the drip irrigation. The growth of two varieties was not significantly different among four substrates in 15 days, but it was excellent in commercial horticultural media (TKS-2) and cocopeat 3 : perlite 7 (v/v) in 20 days. The growth in 'Yeonhwangmiwas' promoted than that in 'Mannami', and the upper-shoot cuttings of 'Yeonhwangmi' and 'Mannami' showed a significant vine elongation (over 10 and 2 cm, respectively) compared to the one-node cuttings. Fresh weight and dry weight in cocopeat 3 : perlite 7 (v/v) were significant increased than that in cocopeat 7 : perlite 3 (v/v). Therefore, the bag culture system filed with cocopeat 3 : perlite 7 (v/v) was successfully applied on propagation of virus-free sweetpotato seedling, and the result expected that the bag culture system could be commercialized without high financial costs for farmers.

• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1727-1738
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• 1996

This paper proposes a extended service filtering technique to solve overload control problems inService Con-trol Poin(SCP) due to Televoting (VOT) services with heavy traffic characteristics. Also, this paper compares this new technique with existing IN overload control lechniques, and calculate steady state call blocking probabilities in In under overload conditions. The proposed technique considers SCP overload and IN CS-1services such as VOT service that need to use the specialized resources of IP. This technique uses first an activating step which SCP sends service filtering request to SSP and IP for the start of service filtering. Then, in the filtering step SSP sendas filtering results to SCP periodically or each N-calls.Also,when filtering time-out timer expired or call counter value exceeded maximum number of calls,SSP stops service filtering,and sends ser-vice filteing response to SCP in the deactivating step. The application of this techique to VOT service defined in IN CS-1 service is investigated and analyzed by using an analytical VOT service model.In order to apply this technique to VOT service, this paper also discusses VOT service and the corresponding N architecture including Service Switching Point(SSP),SCP and IP. Then this paper also constructs an analytical VOT service model,and calculates SCP and SSP/IP(circuit)call blocking probablities.With the application of this new technique,this paper shows good performance enhancements in SCP call blocking probability.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.19-26
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• 2013

In this paper, we present a novel illumination system for parking lots constructed underground. We design and implement this system using microwave sensors and dimming control of LED fluorescent lamps so that we can obtain lighting efficiency of the illumination scheme. We construct an effective illumination system in the aspects of performance and cost, resulting in energy-saving and electricity reduction. Recently conventional energy-saving method applied to old underground parking lots mainly relies upon turning off the half of total number of lamps installed in the parking lot. Sometimes there are some lots that have infrared sensor to be used to turn on/off the fluorescent lamps to realize these operations smoothing. The other schemes utilize timer to control lighting time of the fluorescent lamps. These conventional schemes are forcing to turn off a part of lamps installed so that we cannot apply them in a systematic way. Moreover they will be most inefficient when we leave them alone to be continuous consumers. The lighting control system proposed in this paper can recognize objects through microwave sensors and inform the appropriate lighting time, furthermore we can adjust brightness of LED lamps following the surroundings using dimming control scheme so that we can epochally improve the illumination system for underground parking lots. According to our sophisticated test experiments, we can maximally obtain 81.9% of energy-saving effectiveness using the system proposed in this paper.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.406-419
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• 2017

This study is to explore the essence and meaning of part-time job experience, in particular, to deduce growth experience through part-time jobs. This study is based on time-experience of phenomenological research method developed by the van Manen. For this research, the research data was collected by reviewing high school student part timer in Gyeonggi-do, those who had experience of average of two-year part time work or currently at work, and by undertaking in-depth interviews with seven of them from the March to April of 2017 with the agreements of the participants of this study. Time-experiences, i.e. part-time job experiences of youths, can be arranged as the following subjects. 'the feeling necessity part-time job and seeking it', 'adapting hard life of part-time', growth-experiencing through part-time work..The necessities for part-time job are feeling up consumption needs, aidsing domestic economy, pursuing independence, social and leisure life, self growth and preparing for the future. Adapting of part-time jobs are mastering, enduring, skillfuling work related to work adatation, and enduring ostracizing of old members, stopping and lasting, building bonds related to relationship adaptation. Growth-experiencing through part-time work are formig rational management for money, mental growth, preparing for the future. Based on these findings, the suggestion and limitation of the study were presented.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.482-491
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• 2009

The purpose of this research is to design and develop teacher assistant contents 'My Class' for an intelligent robot iRobiQ, using in early childhood educational setting. After observing daily activities and correspondence role of teachers in educational settings, we selected the robots' target contents as 6 main functions (Attendance, Activity, Gallery, Learning, Role Calling, and Timer). We designed the contents according to the PLU (Player-Learner-User) model which suggests importance of entertainment, education, and enabling features to meet player, learner, and user requirements. We also considered 'emotional' features to satisfy 'companion' requirements. The developed contents in this study was deployed in kindergarten classrooms consisting of five-years-old for 4 weeks to see how they response and use the contents. We found that both teachers and children were likely to show positive responses to the contents. Especially, young children responded to the entertainment and emotional features more actively than to the other features. And they continually explored for something new inside the contents. Finally, this paper discusses what should be considered to develop more useful teacher assistant contents for iRobiQ.

• The Journal of the Korea Contents Association
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• v.15 no.3
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• pp.352-361
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• 2015

Tea is one of the three most consumed drinks in the world along with coffee and cocoa, and it represents culture and tradition. There are more than 1,000 tea-related smartphone applications registered in the Apple App Store and Google Play. This study examined, for the consumers of the 20's, if there are differences in consumer preferences for tea-related applications based on gender, age, tea consumption amount and tea drinking duration. Based on surveys of 169 tea consumers, this study found that there were significant differences in consumer preferences for tea-related applications based on age and tea drinking amount. The applications of 'tea places,' 'entertainment,' and 'tea timer' were preferred by the consumers of 20's and 'etiquette,' 'tea ceremony,' 'teaware,'and 'tea information recording' were favored by the consumers of 30's and older. The consumers with higher drinking amount showed higher preferences for tea etiquette related applications. There were no significant differences for tea-related applications based on gender and tea drinking duration. The result of the study is expected to contribute to the development of tea related applications with higher appeals to consumers as well as traditional Korean drinks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.7
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• pp.1332-1339
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• 2001

SoC(System on Chip) technology is widely used in the field of embedded systems by providing high flexibility for a specific application domain. An important aspect of development any new embedded system is verification which usually requires lengthy software and hardware co-design. To reduce development cost of design effort, the instruction set of microprocessor must be suitable for a high level language compiler. And FPGA prototype system could be derived and tested for design verification. In this paper, we propose a 16 bit FPGA microprocessor, which is tentatively-named EISC16, based on an EISC(Extendable Instruction Set Computer) architecture for embedded applications. The proposed EISC16 has a 16 bit fixed length instruction set which has the short length offset and small immediate operand. A 16 bit offset and immediate operand could be extended using by an extension register and an extension flag. We developed a cross C/C++ compiler and development software of the EISC16 by porting GNU on an IBM-PC and SUN workstation and compared the object code size created after compiling a C/C. standard library, concluding that EISC16 exhibits a higher code density than existing 16 microprocessors. The proposed EISC16 requires approximately 6,000 gates when designed and synthesized with RTL level VHDL at Xilinix's Virtex XCV300 FPGA. And we design a test board which consists of EISC16 ROM, RAM, LED/LCD panel, periodic timer, input key pad and RS-232C controller. 11 works normally at 7MHz Clock.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.79-89
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• 2006

TCP is the most widely used transport protocol in Internet applications that guarantees a reliable data transfer. But, in the wireless multi-hop networks, TCP performance is degraded because it is designed for wired networks. The main reasons of TCP performance degradation are contention for wireless medium at the MAC layer, hidden terminal problem, exposed terminal problem, packet losses in the link layer, unfairness problem, reordering problem caused by path disconnection, bandwidth waste caused by exponential backoff of retransmission timer due to node's mobility and so on. Specially, in the mobile ad-hoc networks, discrepancy between a station's transmission range and interference range produces hidden terminal problem that decreases TCP performance greatly by limiting simultaneous transmission at a time. In this paper, we propose a new MAC algorithm for mobile ad-hoc networks to solve the problem that a node can not transmit and just increase CW by hidden terminal. In the IEEE 802.11 MAC DCF, a node increases CW exponentially when it fails to transmit, but the proposed algorithm, changes CW adaptively according to the reason of failure so we get a TCP performance enhancement. We show by ns-2 simulation that the proposed algorithm enhances the TCP performance by fairly distributing the transmission opportunity to the failed nodes by hidden terminal problems.