• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4D
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• pp.585-594
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• 2011

A variety of PPP (Public-Private Partnerships) schemes including BOT, TOT (Transfer-Operate-Transfer), and divestiture has been employed in the Chinese water sector. Although the two latter emerging models have been implemented in their full applications lately, there has been no follow-up for identification of opportunities and challenges inherent in those schemes in relation to the market participation of foreign investor. This study undertakes in-depth analysis on the TOT and divestiture projects in the SWOT (Strengths, Weaknesses, Opportunities, and Threats) matrix and measures the level of agreement on each SWOT through a survey among the Chinese water market experts. The findings can be used to support foreign investors in managing the weaknesses and threats that, unless properly managed, can be evolved into potential project risks, while fully benefiting from the strengths and opportunities of the two schemes.

• Journal of Plant Biology
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• v.5 no.4
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• pp.1-5
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• 1962

CHA, Jong Whan (Dept. of Biology, College of Education, Seoul National University). Effect of gibberallin on the growth and internal componsents of Astragalus sinicus L. Kor. Jour. Bot. V(4) : 1-5, 1962. The effect of GA on the growth as well as on the internal components of the leaves of Astragalus sinicus L. under the soil culture was investigated. The result has indicated that small variation in the relative concentration of GA treated on the leaves shows a marked influence on the internal components of the plants. The increase of growth was associated with increasing intensity of GA. Chlorophyll and carotene contents in the leaves were depressed with increasing concentration of GA. It was noticed that the growth was pomoted with the decrease of the contents of chlorophyll and carotene. In contrast the aacorbic acid in the leaves treated with GA decreased in proportion to the degree of the concentration of GA. Carotens content varied with chlorophyll, although the ratio of chlorophyll to carotene was not so high as the results obtained by Beck and Redman. Chlorophyll and ascorbic acid values with respect to growth differed greatly during the two experimental periods. The chlorophyll content was found highly significant in this experimental periods. The chlorophyll content was found highly significant in this experiment. As the concentration of GA was increased, it was noticed that there was a reduction of anthocyanin, sucrose, and reducing sugar contents. The anthocyanin content was not so high in this study as in the results obtained from the corn by Jacob Straus.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.8
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• pp.873-877
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• 2010

CAPTCHA is a security tool that prevents the automatic sign-up by a spam or a robot. This CAPTCHA usually depends on the smart readability of humans. However, the common and plain CAPTCHA with text-based system is not difficult to be solved by intelligent web-bot and machine learning tools. In this paper, we propose a new sub-image based CAPTCHA system totally different from the text based system. Our system offers a set of cropped sub-image from a whole digital picture and asks user to identify the correct orientation. Though there are some nice machine learning tools for this job, but they are useless for a cropped sub-images, which was clearly revealed by our experiment. Experiment showed that our sub-image based CAPTCHA is easy to human solver, but very hard to all kinds of machine learning or AI tools. Also our CAPTCHA is easy to be generated automatical without any human intervention.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8A
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• pp.1115-1125
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• 1999

This paper forecasts the number of GMPCS(Global Mobile Communications by Satellite) subscribers in Korea. Since GMPCS adopts nor only a new tecnology cor proved in the market yet, bot also a global service principle, it's service market involves a great deal of nucertainties in terms of technological and regulatory perspectives. This paper develops a modified diffusion which considers those uncertainties by identifying three environmental group of tactors. The parameters of the model are estimated through a scenario-based approach. By assuming a pessimistic and an optimistic scenarios with three environmental group of factors, the model forecasts 4,000 and 7,000 substcribers in the first year, and then 100,000 and 600,000 subscribers in 2005 respectively. The sensitivity analysis of the model also gives an implication of the future market growth. In the early period, regulatoyu and technological issues are found to be relatively important, but, in the later period, the interconnection issues and price-competitiveness will become increasingly important.

• Journal of IKEEE
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• v.22 no.2
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• pp.330-338
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• 2018

As population aging progresses, there is a growing demand for IT technology that can relieve the psychological anxiety of the elderly living alone, recognize the dangerous situation, and check the family members' affection. In this paper, we describe the development of a speech recognition speaker that enable senior users to give simple interactive commands by voice and monitor the status of the user. The speaker analyzes the user's voice, grasps the conversation contents through the chatbot, connects the desired service to the user, and provides the result again by voice. By using this speaker, senior users can feel relaxed by natural conversation, and can monitor the status of danger more easily.

• The Plant Pathology Journal
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• v.16 no.1
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• pp.25-28
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• 2000

The effect of ionic osmotic potential (Ψ$\pi$), and matric potential (Ψm) in the range of -0.2 to -4.0 Mpa on mycelial growth of three species of Pleurotus (P.florida, P.ostrenatus and P.safor-caju) were determined over a range of temperature (15-3$0^{\circ}C$) on a 2% malt extract agar medium and compared with the Ψ$\pi$ effect on growth of two strains of Trichoderma green mould. With the ionic solute KCl, optimun Ψ$\pi$for growth was -0.2 MPa for P.floreda and in the range of -0.2 to -0.5 MPa, with slight growth at -3.0 MPa and with nogrowth at -4.0 MPa. Of the species of Pleurotus, P.florida grew signigicantly slower than the other two species. Growt of the species of Pleurocus was significantly slower when water potential (Ψ$\omega$) was modified matrically with polyethylene glycol (PEG) 8000 then osmotically with KCl. They were also more sensitive to changes in Ψm than Ψ$\pi$The optimum Ψm of the Pleurotus was -0.5 Ψm, with no growth below -3.0 MPa. Of the species of Pleurotus, P.florida was most sensitive and P.sajor-caju was more tolerent to lowered Ψ$\pi$,but P.sajor-caju was most sensitive to lowered Ψm. The growth rate of the Trichoderma green mould strains was much faster than that observed for the Pleurotus spp. Optimum growth for bot strains of Trichoderma was in the range of -0.2 to -0.5 MPa. Strain CNU 503 was more tolerant to water stress than strain CNU 501. Both strains were able to grow up to 30% of optimum growth at -4.0 MPa at 25-3$0^{\circ}C$.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.4
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• pp.370-378
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• 2018

Recent advances in network infrastructures, sensors, and IoT devices have accelerated the research and development of monitoring and interaction technologies designed for people, buildings, and environments. In particular, there has been an increasing demand for monitoring technologies for vulnerable people such as the infirm, disabled, and children. In this paper, we propose an efficient hospital room management system based on IoT care robots. The status of hospital rooms can be monitored and controlled more efficiently and intuitively by utilizing IoT devices and a cloud platform. We demonstrated the feasibility of the proposed system through the implementation of a prototype based on ARTIK IoT devices and the ARTIK Cloud platform. We found that the proposed system requires approximately 600 ms and 130 ms to collect sensor data and respond to alerts, respectively, which demonstrates it can operate in real-time.

• Korean Journal of Logic
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• v.21 no.1
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• pp.59-96
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• 2018

${\bot}$It is often said that in a purely formal perspective, intuitionistic logic has no obvious advantage to deal with the liar-type paradoxes. In this paper, we will argue that the standard intuitionistic natural deduction systems are vulnerable to the liar-type paradoxes in the sense that the acceptance of the liar-type sentences results in inference to absurdity (${\perp}$). The result shows that the restriction of the Double Negation Elimination (DNE) fails to block the inference to ${\perp}$. It is, however, not the problem of the intuitionistic approaches to the liar-type paradoxes but the lack of expressive power of the standard intuitionistic natural deduction system. We introduce a meta-level negation, ⊬$_s$, for a given system S and a meta-level absurdity, ⋏, to the intuitionistic system. We shall show that in the system, the inference to ${\perp}$ is not given without the assumption that the system is complete. Moreover, we consider the Double Meta-Level Negation Elimination rules (DMNE) which implicitly assume the completeness of the system. Then, the restriction of DMNE can rule out the inference to ${\perp}$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.744-748
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• 2012

Botnet is a network that consists of bot hosts infected by malware. The C&C server of centralized botnet, which is being used widely, is relatively easy to detect, while detecting P2P botnet is not a trivial problem because of the existence of many avoiding techniques. In this paper, we separate the network into inner and outer sub-network at the location of the router, and analyze the method of detecting botnet using path of packet and infection probability. We have extended Dye-Pumping algorithm in order to detect P2P botnet members more accurately, and we expect that the analysis of the results can be used as a basis of techniques that detect and block P2P botnet in the networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.5
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• pp.1445-1462
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• 2012

While botnets are used for various malicious activities, it is well known that they are widely used for email spam. Though the spam filtering systems currently in use block IPs that send email spam, simply blocking the IPs of zombie PCs participating in a botnet is not enough to prevent the spamming activities of the botnet because these IPs can easily be changed or manipulated. This IP blocking is also insufficient to prevent crimes other than spamming, as the botnet can be simultaneously used for multiple purposes. For this reason, we propose a system that detects botnets and zombie PCs based on email spam analysis. This study introduces the concept of "group pollution level" - the degree to which a certain spam group is suspected of being a botnet - and "IP pollution level" - the degree to which a certain IP in the spam group is suspected of being a zombie PC. Such concepts are applied in our system that detects botnets and zombie PCs by grouping spam mails based on the URL links or attachments contained, and by assessing the pollution level of each group and each IP address. For empirical testing, we used email spam data collected in an "email spam trap system" - Korea's national spam collection system. Our proposed system detected 203 botnets and 18,283 zombie PCs in a day and these zombie PCs sent about 70% of all the spam messages in our analysis. This shows the effectiveness of detecting zombie PCs by email spam analysis, and the possibility of a dramatic reduction in email spam by taking countermeasure against these botnets and zombie PCs.