• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.3
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• pp.266-273
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• 2007

The change patterns of the water quanity, water quality(WQ, exclusively COD in this study) and monthly / annual pollutant loads(PL) estimated using the daily effluent discharges and WQ measurement data are analyzed in the Nakdong river estuarine seadike. The contribution factor defined by the ratio of the water quantity range and WQ range shows that the PL pattern in this estuary is classified as the strongly flow(water quantity)-dominated situation. The estimated PL(EPL)s with respect to the increasing sampling periods, e.g., 2-days, 5-days, 7-days, and so on, show that the mean values of the EPLs remain nearly same, whereas the standard deviations of the EPLs have an obvious increasing trend. The PL values using the monthly-averaged water quantity and WQ measurement data could have approximately 100% estimation error in annual mean and $300\sim400%$ estimation errors in summer season because its confidence level is relatively low. It is recommended that the PL should be estimated using at least $10\sim20$ day interval data sets and also the water quantity(river discharges) and WQ should be measured at the intervals of at least 1 day interval and 5 to 7 days, respectively in summer.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1749-1758
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• 1997

This paper suggests the development of dynamic forecasting model for short-term power demand based on Radial Basis Function Network and Pal's GLVQ algorithm. Radial Basis Function methods are often compared with the backpropagation training, feed-forward network, which is the most widely used neural network paradigm. The Radial Basis Function Network is a single hidden layer feed-forward neural network. Each node of the hidden layer has a parameter vector called center. This center is determined by clustering algorithm. Theatments of classical approached to clustering methods include theories by Hartigan(K-means algorithm), Kohonen(Self Organized Feature Maps %3A SOFM and Learning Vector Quantization %3A LVQ model), Carpenter and Grossberg(ART-2 model). In this model, the first approach organizes the load pattern into two clusters by Pal's GLVQ clustering algorithm. The reason of using GLVQ algorithm in this model is that GLVQ algorithm can classify the patterns better than other algorithms. And the second approach forecasts hourly load patterns by radial basis function network which has been constructed two hidden nodes. These nodes are determined from the cluster centers of the GLVQ in first step. This model was applied to forecast the hourly loads on Mar. $4^{th},\;Jun.\;4^{th},\;Jul.\;4^{th},\;Sep.\;4^{th},\;Nov.\;4^{th},$ 1995, after having trained the data for the days from Mar. $1^{th}\;to\;3^{th},\;from\;Jun.\;1^{th}\;to\;3^{th},\;from\;Jul.\;1^{th}\;to\;3^{th},\;from\;Sep.\;1^{th}\;to\;3^{th},\;and\;from\;Nov.\;1^{th}\;to\;3^{th},$ 1995, respectively. In the experiments, the average absolute errors of one-hour ahead forecasts on utility actual data are shown to be 1.3795%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.4
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• pp.318-327
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• 2017

It is essential for the near-field receiving measurement to make beam pattern and check the performance of a active phased array antenna system. Also, we could obtain compensation value for mono-pulse function through the near-field receive test, however, if the radar has many frequency channel, the test would take long time and hard effort. So it is needed that frequency channels are selected for measurement and calculates the values for other frequency channels to improve efficiency in development and manufacture. In this case, the phase variations in sum and del channels would be checked. The phase measurement includes un-linear characteristic because of wrapping effect. Generally, radars have similar path length in sum and del channel, but if a radar has a electrical length gap between sum and del channel, errors could occur by phase's wrapping effect. In this paper, the interpolation method's error caused by electrical length gap is checked and the effective method for frequency channel selection to avoid wrapping effect is introduced.

• Journal of The Korean Association For Science Education
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• v.18 no.4
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• pp.503-516
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• 1998

The purpose of the present study was to evaluate some variables, such as learner's cognitive characteristics and a training-program emphasized proportional logic, in proportional reasoning development. Seven hundred and ninety students in junior high schools were enrolled as subjects for the study which investigated learner's cognitive characteristics in proportional reasoning development and asked to perform tests of logical thinking, card sorting, planning, mental capacity, cognitive style, brain lateralization, information processing pattern and scientific reasoning. In addition, one hundred and thirty-three students who failed to solve proportional thinking items were administered a training program which has been applied to improve the subjects' proportional reasoning skills. The results showed a significant higher correlation between subjects' performance score on proportional thinking test, and their age and scores on scientific reasoning test, mental capacity, information processing test and perseveration errors on card sorting test. Also, the training program applied in this study showed an effective result in developing subjects' proportional reasoning skills. Further, this study may serve as a suggestion in the efforts to investigate factors of proportional thinking development and a contribution for the future research in other logical thinking development.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.275-286
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• 2001

Purpose : To setup procedures of quality assurance (OA) for implementing intensity modulated radiation therapy (IMRT) clinically, report OA procedures peformed for one patient with prostate cancer. Materials and methods : $P^3IMRT$ (ADAC) and linear accelerator (Siemens) with multileaf collimator are used to implement IMRT. At first, the positional accuracy, reproducibility of MLC, and leaf transmission factor were evaluated. RTP commissioning was peformed again to consider small field effect. After RTP recommissioning, a test plan of a C-shaped PTV was made using 9 intensity modulated beams, and the calculated isocenter dose was compared with the measured one in solid water phantom. As a patient-specific IMRT QA, one patient with prostate cancer was planned using 6 beams of total 74 segmented fields. The same beams were used to recalculate dose in a solid water phantom. Dose of these beams were measured with a 0.015 cc micro-ionization chamber, a diode detector, films, and an array detector and compared with calculated one. Results : The positioning accuracy of MLC was about 1 mm, and the reproducibility was around 0.5 mm. For leaf transmission factor for 10 MV photon beams, interleaf leakage was measured $1.9\%$ and midleaf leakage $0.9\%$ relative to $10\times\;cm^2$ open filed. Penumbra measured with film, diode detector, microionization chamber, and conventional 0.125 cc chamber showed that $80\~20\%$ penumbra width measured with a 0.125 cc chamber was 2 mm larger than that of film, which means a 0.125 cc ionization chamber was unacceptable for measuring small field such like 0.5 cm beamlet. After RTP recommissioning, the discrepancy between the measured and calculated dose profile for a small field of $1\times1\;cm^2$ size was less than $2\%$. The isocenter dose of the test plan of C-shaped PTV was measured two times with micro-ionization chamber in solid phantom showed that the errors upto $12\%$ for individual beam, but total dose delivered were agreed with the calculated within $2\%$. The transverse dose distribution measured with EC-L film was agreed with the calculated one in general. The isocenter dose for the patient measured in solid phantom was agreed within $1.5\%$. On-axis dose profiles of each individual beam at the position of the central leaf measured with film and array detector were found that at out-of-the-field region, the calculated dose underestimates about $2\%$, at inside-the-field the measured one was agreed within $3\%$, except some position. Conclusion : It is necessary more tight quality control of MLC for IMRT relative to conventional large field treatment and to develop QA procedures to check intensity pattern more efficiently. At the conclusion, we did setup an appropriate QA procedures for IMRT by a series of verifications including the measurement of absolute dose at the isocenter with a micro-ionization chamber, film dosimetry for verifying intensity pattern, and another measurement with an array detector for comparing off-axis dose profile.

• Journal of Global Scholars of Marketing Science
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• v.19 no.3
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• pp.17-27
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• 2009

Price promotion typically reduces the price for a given quantity or increases the quantity available at the same price, thereby enhancing value and creating an economic incentive to purchase. It often is used to encourage product or service trial among nonusers of products or services. Thus, it is important to understand the effects of price promotions on quality perception made by consumer who do not have prior experience with the promoted brand. However, if consumers associate a price promotion itself with inferior brand quality, the promotion may not achieve the sales increase the economic incentives otherwise might have produced. More specifically, low qualitative perception through price promotion will undercut the economic and psychological incentives and reduce the likelihood of purchase. Thus, it is important for marketers to understand how price promotional informations about a brand have impact on consumer's unfavorable quality perception of the brand. Previous literatures on the effects of price promotions on quality perception reveal inconsistent explanations. Some focused on the unfavorable effect of price promotion on consumer's perception. But others showed that price promotions didn't raise unfavorable perception on the brand. Prior researches found these inconsistent results related to the timing of the price promotion's exposure and quality evaluation relative to trial. And, whether the consumer has been experienced with the product promotions in the past or not may moderate the effects. A few studies considered differences among product categories as fundamental factors. The purpose of this research is to investigate the effect of price promotional informations on consumer's unfavorable quality perception under the different conditions. The author controlled the timing of the promotional exposure and varied past promotional patterns and information presenting patterns. Unlike previous researches, the author examined the effects of price promotions setting limit to pretrial situation by controlling potentially moderating effects of prior personal experience with the brand. This manipulations enable to resolve possible controversies in relation to this issue. And this manipulation is meaningful for the work sector. Price promotion is not only used to target existing consumers but also to encourage product or service trial among nonusers of products or services. Thus, it is important for marketers to understand how price promotional informations about a brand have impact on consumer's unfavorable quality perception of the brand. If consumers associate a price promotion itself with inferior quality about unused brand, the promotion may not achieve the sales increase the economic incentives otherwise might have produced. In addition, if the price promotion ends, the consumer that have purchased that certain brand will likely to display sharply decreased repurchasing behavior. Through a literature review, hypothesis 1 was set as follows to investigate the adjustive effect of past price promotion on quality perception made by consumers; The influence that price promotion of unused brand have on quality perception made by consumers will be adjusted by past price promotion activity of the brand. In other words, a price promotion of an unused brand that have not done a price promotion in the past will have a unfavorable effect on quality perception made by consumer. Hypothesis 2-1 was set as follows : When an unused brand undertakes price promotion for the first time, the information presenting pattern of price promotion will have an effect on the consumer's attribution for the cause of the price promotion. Hypothesis 2-2 was set as follows : The more consumer dispositionally attribute the cause of price promotion, the more unfavorable the quality perception made by consumer will be. Through test 1, the subjects were given a brief explanation of the product and the brand before they were provided with a $2{\times}2$ factorial design that has 4 patterns of price promotion (presence or absence of past price promotion * presence or absence of current price promotion) and the explanation describing the price promotion pattern of each cell. Then the perceived quality of imaginary brand WAVEX was evaluated in the scale of 7. The reason tennis racket was chosen is because the selected product group must have had almost no past price promotions to eliminate the influence of average frequency of promotion on the value of price promotional information as Raghubir and Corfman (1999) pointed out. Test 2 was also carried out on students of the same management faculty of test 1 with tennis racket as the product group. As with test 1, subjects with average familiarity for the product group and low familiarity for the brand was selected. Each subjects were assigned to one of the two cells representing two different information presenting patterns of price promotion of WAVEX (case where the reason behind price promotion was provided/case where the reason behind price promotion was not provided). Subjects looked at each promotional information before evaluating the perceived quality of the brand WAVEX in the scale of 7. The effect of price promotion for unfamiliar pretrial brand on consumer's perceived quality was proved to be moderated with the presence or absence of past price promotion. The consistency with past promotional behavior is important variable that makes unfavorable effect on brand evaluations get worse. If the price promotion for the brand has never been carried out before, price promotion activity may have more unfavorable effects on consumer's quality perception. Second, when the price promotion of unfamiliar pretrial brand was executed for the first time, presenting method of informations has impact on consumer's attribution for the cause of firm's promotion. And the unfavorable effect of quality perception is higher when the consumer does dispositional attribution comparing with situational attribution. Unlike the previous studies where the main focus was the absence or presence of favorable or unfavorable motivation from situational/dispositional attribution, the focus of this study was exaus ing the fact that a situational attribution can be inferred even if the consumer employs a dispositional attribution on the price promotional behavior, if the company provides a persuasive reason. Such approach, in academic perspectih sis a large significance in that it explained the anchoring and adjng ch approcedures by applying it to a non-mathematical problem unlike the previous studies where it wis ionaly explained by applying it to a mathematical problem. In other wordn, there is a highrspedency tmatispositionally attribute other's behaviors according to the fuedach aal attribution errors and when this is applied to the situation of price promotions, we can infer that consumers are likely tmatispositionally attribute the company's price promotion behaviors. Ha ever, even ueder these circumstances, the company can adjng the consumer's anchoring tmareduce the po wibiliute thdispositional attribution. Furthermore, unlike majority of previous researches on short/long-term effects of price promotion that only considered the effect of price promotions on consumer's purchasing behaviors, this research measured the effect on perceived quality, one of man elements that affects the purchasing behavior of consumers. These results carry useful implications for the work sector. A guideline of effectively providing promotional informations for a new brand can be suggested through the outcomes of this research. If the brand is to avoid false implications such as inferior quality while implementing a price promotion strategy, it must provide a clear and acceptable reasons behind the promotion. Especially it is more important for the company with no past price promotion to provide a clear reason. An inconsistent behavior can be the cause of consumer's distrust and anxiety. This is also one of the most important factor of risk of endless price wars. Price promotions without prior notice can buy doubt from consumers not market share.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.4
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• pp.151-171
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• 2017

Most of oceanic current maps in the secondary school science and earth science textbooks have been made on the base of extensive in-situ measurements conducted by Japanese oceanographers during 1930s. According to up-to-date scientific knowledge on the currents in the Yellow Sea and the East China Sea (YES), such maps have significant errors and are likely to cause misconceptions to students, thus new schematic map of ocean currents is needed. The currents in the YES change seasonally due to relatively shallow water depths, complex terrain, winds, and tides. These factors make it difficult to construct a unified ocean current map of the YES. Sixteen major items, such as the flow of the Kuroshio Current into the East China Sea and its northward path, the origin of the Tsushima Warm Current and its path into the Korea Strait, the path of Taiwan Warm Current, the Jeju Warm Current, the runoff pattern of the Yangtze River flow, the routes of the northward Yellow Sea Warm Current, the Chinese Coastal Current, and the West Korea Coastal Current off the west coast of the Korean Peninsula, were selected to produce the schematic current map. Review of previous scientific researches, in-depth discussions through academic conferences, expert discussions, and consultations for three years since 2014 enabled us to produce the final ocean current maps for the YES after many revisions. Considering the complexity of the ocean currents, we made seven ocean current maps: two representative current patterns in summer and winter, seasonal current maps for upper layer and lower layer in summer and winter, and one representative surface current map. It is expected that the representative maps of the YES, connected to the current maps of the East Sea and the Northwest Pacific Ocean, would be widely utilized for diverse purposes in the secondary-school textbooks as well as high-level educational purposes and even for scientific scholarly experts.

• Economic and Environmental Geology
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• v.43 no.6
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• pp.625-636
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• 2010

The geophysical characteristics and geological structure of the northeastern part of the Ulleung Basin were investigated from interpretation of geophysical data including gravity, magnetic, bathymetry data, and seismic data. Relative correction was applied to reduce errors between sets of gravity and magnetic data, obtained at different times and by different equipments. The northeastern margin of the Ulleung Basin is characterized by complicated morphology consisting of volcanic islands (Ulleungdo and Dokdo), the Dokdo seamounts, and a deep pathway (Korea Gap) with the maximum depth of -2500 m. Free-air anomalies generally reflect the topography effect. There are high anomalies over the volcanic islands and the Dokdo seamounts. Except local anomalous zones of volcanic edifices, the gradual increasing of the Bouguer anomalies from the Oki Bank toward the Ulleung Basin and the Korea Gap is related to higher mantle level and denser crust in the central of the Ulleung Basin. Complicated magnetic anomalies in the study area occur over volcanic islands and seamounts. The power spectrum analysis of the Bouguer anomalies indicates that the depth to the averaged Moho discontinuity is -16.1 km. The inversion of the Bouguer anomaly shows that the Moho depth under the Korea Gap is about -16~17 km and the Moho depths towards the Oki Bank and the northwestern part of Ulleung Island are gradually deeper. The inversion result suggests that the crust of the Ulleung Basin is thicker than normal oceanic crusts. The result of 20 gravity modeling is in good agreement with the results of the power spectrum analysis and the inversion of the Bouguer anomaly. Except the volcanic edifices, the main pattern of magnetization distribution shows lineation in NE-SW. The inversion results, the 2D gravity modeling, and the magnetization distribution support possible NE-SW spreading of the Ulleung Basin proposed by other papers.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.169-187
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• 2023

Aggregates from 84 cities and counties in Korea were tested for quality to allow analysis of the physical characteristics of aggregates from river, land, and forest environments. River and land aggregates were analyzed for 18 test items, and forest aggregates for 12 test items. They were classified according to watershed and geology, respectively. The observed physical characteristics of the river aggregates by basin were as follows: aggregates from the Geum River basin passed through 2.5, 1.2, 0.6, 0.3, 0.15, and 0.08 mm sieves; clay lumps constituted the Nakdong River basin material; aggregates from the Seomjin River basin passed through 10, 5, and 2.5 mm sieves; those from the Youngsang River basin passed through 1.2, 0.6, 0.3, 0.15, and 0.08 mm sieves; and aggregates from the Han River basin passed through 10, 5, 2.5, 1.2, 0.6, 0.3, and 0.08 mm sieves, Stability; Standard errors were analyzed for the average amount passing through 10, 0.6, and 0.08 mm silver sieves, and performance rate showed different distribution patterns from other physical characteristics. Analysis of variance found that 16 of the 18 items, excluding the absorption rate and the performance rate, had statistically significant differences in their averages by region. Considering land aggregates by basin, those from the Nakdong River basin excluding the Geum River basin had clay lumps, those from the Seomjin River basin had 10 and 5 mm sieve passage, aggregates from the Youngsang River basin had 0.08 mm sieve passage, and those from the Han River basin had 10, 0.6, and 0.08 mm sieve passage. The standard error of the mean of the quantity showed a different distribution pattern from the other physical characteristics. Analysis of variance found a statistically significant difference in the average of all 18 items by region. Analyzing forest aggregates by geology showed distributions of porosity patterns different from those of other physical characteristics in metamorphic rocks (but not igneous rocks), and distributions of wear rate and porosity were different from those of sedimentary rocks. There were statistically significant differences in the average volume mass, water absorption rate, wear rate, and Sc/Rc items by lipid.

• Journal of Intelligence and Information Systems
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• v.17 no.4
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• pp.157-173
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• 2011

As the Internet use explodes recently, the malicious attacks and hacking for a system connected to network occur frequently. This means the fatal damage can be caused by these intrusions in the government agency, public office, and company operating various systems. For such reasons, there are growing interests and demand about the intrusion detection systems (IDS)-the security systems for detecting, identifying and responding to unauthorized or abnormal activities appropriately. The intrusion detection models that have been applied in conventional IDS are generally designed by modeling the experts' implicit knowledge on the network intrusions or the hackers' abnormal behaviors. These kinds of intrusion detection models perform well under the normal situations. However, they show poor performance when they meet a new or unknown pattern of the network attacks. For this reason, several recent studies try to adopt various artificial intelligence techniques, which can proactively respond to the unknown threats. Especially, artificial neural networks (ANNs) have popularly been applied in the prior studies because of its superior prediction accuracy. However, ANNs have some intrinsic limitations such as the risk of overfitting, the requirement of the large sample size, and the lack of understanding the prediction process (i.e. black box theory). As a result, the most recent studies on IDS have started to adopt support vector machine (SVM), the classification technique that is more stable and powerful compared to ANNs. SVM is known as a relatively high predictive power and generalization capability. Under this background, this study proposes a novel intelligent intrusion detection model that uses SVM as the classification model in order to improve the predictive ability of IDS. Also, our model is designed to consider the asymmetric error cost by optimizing the classification threshold. Generally, there are two common forms of errors in intrusion detection. The first error type is the False-Positive Error (FPE). In the case of FPE, the wrong judgment on it may result in the unnecessary fixation. The second error type is the False-Negative Error (FNE) that mainly misjudges the malware of the program as normal. Compared to FPE, FNE is more fatal. Thus, when considering total cost of misclassification in IDS, it is more reasonable to assign heavier weights on FNE rather than FPE. Therefore, we designed our proposed intrusion detection model to optimize the classification threshold in order to minimize the total misclassification cost. In this case, conventional SVM cannot be applied because it is designed to generate discrete output (i.e. a class). To resolve this problem, we used the revised SVM technique proposed by Platt(2000), which is able to generate the probability estimate. To validate the practical applicability of our model, we applied it to the real-world dataset for network intrusion detection. The experimental dataset was collected from the IDS sensor of an official institution in Korea from January to June 2010. We collected 15,000 log data in total, and selected 1,000 samples from them by using random sampling method. In addition, the SVM model was compared with the logistic regression (LOGIT), decision trees (DT), and ANN to confirm the superiority of the proposed model. LOGIT and DT was experimented using PASW Statistics v18.0, and ANN was experimented using Neuroshell 4.0. For SVM, LIBSVM v2.90-a freeware for training SVM classifier-was used. Empirical results showed that our proposed model based on SVM outperformed all the other comparative models in detecting network intrusions from the accuracy perspective. They also showed that our model reduced the total misclassification cost compared to the ANN-based intrusion detection model. As a result, it is expected that the intrusion detection model proposed in this paper would not only enhance the performance of IDS, but also lead to better management of FNE.