• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.147-154
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• 2006

The certificate status validation mechanism is a critical component of a public key infrastructure based on certificate system. The most generally mechanisms used these days are the use of the certificate revocation list and the real-time certificate status protocol. But the certificate revocation list can not give the real-time certificate status because the certificate is being delivered periodically, and the real-time certificate status protocol method will generate a concentrated load to the server because the protocol in the central server will be accessed whenever a certification is necessary. It will also take a long time to validate the certificate because each trade has to send mass information through the network. This paper will present that real-time validation is guaranteed as the real-time certificate status protocol method and the traffic congestion in the network Is reduced in a way that the certification would be requested using the user information hash value and would be validated using the user information kept in the certification authorities and the service providers. Based on the this study, we suggest a real-time certificate status validation mechanism which can reduce the certificate status validation time using the signed user information hash value. And we confirm speed of certificate status verification faster than existing CRL(Certificate Revocation List) and OCSP(Online Certificate Status Protocol) method by test.

• KDI Journal of Economic Policy
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• v.26 no.1
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• pp.3-33
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• 2004

This paper investigates the effects of inflation on real estate prices, particularly the discrepancy between the sales and chonsei prices of housing, in an economy in which real interest rates are secularly declining due to the fall in capital productivity. When real interest rates fall, real estate prices rise relative to chonsei prices, and thus the well-known adverse effect of inflation, or the discrepancy between the value of financial assets (or chonsei principal) and the value of real assets (or real estate), is aggravated although the monetary authority maintains the same rate of inflation. This theoretical prediction can help explain the trend of the ratio of apartment sales prices to chonsei prices. That is, the stabilization of inflation relative to real interest rates appears to have contributed to the secular stabilization of this ratio in the 1990s, while the fall in real interest rates appears to have led to the rise of this ratio since 2001.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.230-232
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• 2021

As the ratio of double-income households and parental leave use increase, there is an increasing demand for products that help when raising children alone. In particular, there is a lot of demand for baby beds that help raise children without difficulty even by themselves. Therefore, in this paper, we propose a real-time monitoring of a smart crib using a sound sensor. The proposed bed uses a sound sensor to detect the child's crying and condition, and the measured sensor output value can be checked with a mobile application. When the sound sensor output value is more than a certain value, a voice file such as a lullaby recorded with the voice of the parents is played, and if the sensor output value is less than a certain value, the playing voice file is stopped. If the sensor output value continues to exist after a certain period of time, a pop-up notification is sent to the mobile application. This allows the child to quickly calm down with a sense of stability and comfort through the recorded voices of the parents, and the parents can remotely monitor the child's condition in real time.

• Journal of the Speleological Society of Korea
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• no.76
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• pp.67-69
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• 2006

• Journal of Educational Research in Mathematics
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• v.13 no.1
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• pp.77-94
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• 2003

This study attempts to compare the topic "approximate value" in mathematics text-books of the 2nd year of South Korean junior high schools and that of the 3rd year of North Korean high schools. In addition, a survey questionnaire was distributed to junior and senior high school students as well as to mathematics teachers in South Korea. Based on the results of the survey, this study attempts to uncover the issues within the current teaching methods of "approximate value" and proposes the directions in which the teaching of approximate value should go in order to enhance mathematical thinking power and creativity of the students. First, it Is necessary to teach students how an error applies to the real world. To accomplish this end, it may be worthwhile to consider introducing the relative errors with more seriousness. Second, it is more important to teach the way of thinking which is concealed in the background of the calculation methods of approximate values than to simply teach mere calculation methods. Third, it is necessary to teach the calculation of approximate value with more realistic examples. Fourth, It is needed to teach students what the differences are when the terminology of "approximately" and "about" is used in real life and in mathematics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3966-3991
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• 2018

Due to the lack of visualization services and organic combinations between public and private buildings data, the usability of the basic map has remained low. To address this issue, this paper reports on a solution that organically combines public and private data while providing visualization services to general users. For this purpose, factors that can affect building prices first were examined in order to define the related data attributes. To extract the relevant data attributes, this paper presents a method of acquiring public information data and real estate-related information, as provided by private real estate portal sites. The paper also proposes a pretreatment process required for intelligent machine learning. This report goes on to suggest an intelligent machine learning algorithm that predicts buildings' value pricing and future value by using big data regarding buildings' spatial information, as acquired from a database containing building value attributes. The algorithm's availability was tested by establishing a prototype targeting pilot areas, including Suwon, Anyang, and Gunpo in South Korea. Finally, a prototype visualization solution was developed in order to allow general users to effectively use buildings' value ranking and value pricing, as predicted by intelligent machine learning.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.05a
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• pp.222-229
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• 2002

A value net is a business design that uses digital supply chain concepts to achieve both superior customer satisfaction and company profitability. In order to implement the value net model, information processing and distribution needs to occur in real time. Software agent technology is becoming popular due to the inherent characteristics of autonomy, distributedness and modularity. In this paper, we adopt agent technology to handle all real time decision process, making the value net model a complex multi-agent network of decision makers. For the agents to properly coordinate their respective activities we develop MAVN model, a Web-based multi-agent language grounded in the XML and Java.

• The Journal of Society for e-Business Studies
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• v.24 no.2
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• pp.125-141
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• 2019

This paper provides economic analysis for a residential photovoltaic (PV) power system of 5 districts in China and Thailand, using SAM (System Advisor Model) data. Unlike existing literature, the analysis is conducted from the investment timing perspective, as applying to a real option model which can incorporate the cost uncertainty of the PV system and a resident's option to delay the investment. This study shows that the gap of optimal investment times between a real option model and a generally used net present value model ranges from about 6 to 14 years. Also, we found a contracting result for a particular district that, while the investment is appropriate according to the net present value model, it is more reasonable to delay the PV system investment in terms of the real option model.

• Journal of Environmental Health Sciences
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• v.9 no.2
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• pp.75-81
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• 1983

The Biochemical Oxygen Demand(BOD) indicates that microbes are proliferating or that oxygen is being spent by breathing action when examining water under the same aerobic condition. In this research of the mesurement of BOD are the poisonous elements of heavy metal ions such as Cu-ion, Cr-ion, Pb-ion and Zn-ion. They exert an unfavorable influence in the analysis of BOD and research was performed to provide certain data of minimum negative influence by the poisonous matters. The results of the research confirm that heavy metal ion(Cu, Cr, Pb, Zn) do direct an influence upon the normal growth of aerobic microbes in actual tests of chemical analysis of portable water or sewage. The most critical concentration for a negative effect on lowering oxygen quantity and disturbing the aerobic mocrobes normal growth was found to be 0.01 mg/l. Therefore, test results are not valid if the heavy metal concentration is to or greater than 0.0mg/l, To improve comprehension through out the research the author uses the following abbreviations: 1. The Cu-ion is to be excluded before experimental analysis if it is over 0.01mg/l inorder to obtain a real value for the BOD. 2. The Cr-ion is to be excluded before experimental analysis if it is over 0.01mg/l in order to obtain a real value for the BOD. 3. The Pb-ion is to be excluded before experimental analysis if it is over 0.01mg/l in order to obtain a real value for the BOD. 4. The Zn-ion is to be excluded before experimental analysis if it is over 0.01mg/l in order to obtain a real value for the BOD.

• Journal of Korea Technology Innovation Society
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• v.20 no.3
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• pp.732-753
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• 2017

Recently, when evaluating the technology values in the fields of biotechnology, pharmaceuticals and medicine, we have needed more to estimate those values in consideration of the period and cost for the commercialization to be put into in future. The existing discounted cash flow (DCF) method has limitations in that it can not consider consecutive investment or does not reflect the probabilistic property of commercialized input cost of technology-applied products. However, since the value of technology and investment should be considered as opportunity value and the information of decision-making for resource allocation should be taken into account, it is regarded desirable to apply the concept of real options, and in order to reflect the characteristics of business model for the target technology into the concept of volatility in terms of stock price which we usually apply to in evaluation of a firm's value, we need to consider 'the continuity of stock price (relatively minor change)' and 'positive condition'. Thus, as discussed in a lot of literature, it is necessary to investigate the relationship among volatility, underlying asset values, and cost of commercialization in the Black-Scholes model for estimating the technology value based on real options. This study is expected to provide more elaborated real options model, by mathematically deriving whether the ratio of the present value of the underlying asset to the present value of the commercialization cost, which reflects the uncertainty in the option pricing model (OPM), is divided into the "no action taken" (NAT) area under certain threshold conditions or not, and also presenting the estimation logic for option values according to the observation variables (or input values).