• The Journal of Advanced Prosthodontics
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• v.6 no.1
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• pp.1-7
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• 2014

PURPOSE. The accuracy of a gypsum model (GM), which was taken using a conventional silicone impression technique, was compared with that of a polyurethane model (PM), which was taken using an iTero$^{TM}$ digital impression system. MATERIALS AND METHODS. The maxillary first molar artificial tooth was selected as the reference tooth. The GMs were fabricated through a silicone impression of a reference tooth, and PMs were fabricated by a digital impression (n=9, in each group). The reference tooth and experimental models were scanned using a 3 shape convince$^{TM}$ scan system. Each GM and PM image was superimposed on the registered reference model (RM) and 2D images were obtained. The discrepancies of the points registered on the superimposed images were measured and defined as GM-RM group and PM-RM group. Statistical analysis was performed using a Student's T-test (${\alpha}=0.05$). RESULTS. A comparison of the absolute value of the discrepancy revealed a significant difference between the two groups only at the occlusal surface. The GM group showed a smaller mean discrepancy than the PM group. Significant differences in the GM-RM group and PM-RM group were observed in the margins (point a and f), mesial mid-axial wall (point b) and occlusal surfaces (point c and d). CONCLUSION. Under the conditions examined, the digitally fabricated polyurethane model showed a tendency for a reduced size in the margin than the reference tooth. The conventional gypsum model showed a smaller discrepancy on the occlusal surface than the polyurethane model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.4
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• pp.269-275
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• 2017

$NO_X$ reducing technique such as LNT, LNC, and selective catalytic reduction (SCR) have been developed and applied, especially on heavy-duty vehicles. However, it is expected that $NO_X$ reduction techniques will also be applied to diesel passenger vehicles. The urea-SCR system is receiving attention as the most effective $NO_X$ reduction technology without a fuel penalty. Thus, many advanced countries are developing this technology. The urea-SCR system sprays an aqueous urea solution that separates $NO_X$ into $N_2$ and $H_2O$, which are harmless and emitted into the atmosphere. The urea injected in front of the SCR catalyst should be changed to 100％ $NH_3$, which is required for $NO_X$ reduction in the SCR system to maximize the reduction efficiency. The purpose of this study was to determine the basic data for the urea-SCR system to maximize the $NO_X$ reduction efficiency by understanding the $NO_X$ reduction characteristics in a real passenger vehicle to comply with the post EURO-6 emission regulation.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.3
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• pp.116-126
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• 1993

The finite element method(FEM) has been commonly used for structural dynamic analysis. However, the direct global application of FEM to large complex structures such as ships and offshore structures requires considerable computational efforts, and remarkably more in structural dynamic optimization problems. Adoption of the component-mode synthesis method is an efficient means to overcome the above difficulty. Among three classes of the component-mode synthesis method, the free-interface mode method is recognized to have the advantages of better computational efficiency and easier implementation of substructures' experimental results, but the disadvantage of lower accuracy in analytical results. In this paper, an advanced method to improve the accuracy in the application of the free-interface mode method for the vibration analysis of large complex structures is presented. In order to compensate the truncation effect of the higher modes of substructures in the synthesis process, both residual inertia and stiffness effects are taken into account and a frequency shifting technique is introduced in the formulation of the residual compliance of substructures. The introduction of the frequency shrift ins not only excludes cumbersome manipulation of singular matrices for semi-definite substructural systems but gives more accurate results around the specified shifting frequency. Numerical examples of typical structural models including a ship-like two dimensional finite element model show that the analysis results based on the presented method are well competitive in accuracy with those obtained by the direst global FEM analysis for the frequencies which are lower than the highest one employed in the synthesis with remarkably higher computational efficiency and that the presented method is more efficient and accurate than the fixed-interface mode method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.573-581
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• 2020

Using CCTV images and weather parameters, a method for estimating PM (Particulate Matter) index was proposed, and an experiment was conducted. For CCTV images, we proposed a method of estimating the PM index by applying a deep learning technique based on a CNN (Convolutional Neural Network) with ROI(Region Of Interest) image including a specific spot and an full area image. In addition, after combining the predicted result values by deep learning with the two weather parameters of humidity and wind speed, a post-processing experiment was also conducted to calculate the modified PM index using the learned regression model. As a result of the experiment, the estimated value of the PM index from the CCTV image was R2(R-Squared) 0.58~0.89, and the result of learning the ROI image and the full area image with the measuring device was the best. The result of post-processing using weather parameters did not always show improvement in accuracy in all cases in the experimental area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.1
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• pp.15-22
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• 2022

In order to improve the accuracy of the deep learning object detection technique, the effect of magnification rate conditions and seasonal factors on detection accuracy in aerial photographs and drone images was analyzed through experiments. Among the deep learning object detection techniques, Mask R-CNN, which shows fast learning speed and high accuracy, was used to detect the vehicle to be detected in pixel units. Through Seoul's aerial photo service, learning images were captured at different screen magnifications, and the accuracy was analyzed by learning each. According to the experimental results, the higher the magnification level, the higher the mAP average to 60%, 67%, and 75%. When the magnification rates of train and test data of the data set were alternately arranged, low magnification data was arranged as train data, and high magnification data was arranged as test data, showing a difference of more than 20% compared to the opposite case. And in the case of drone images with a seasonal difference with a time difference of 4 months, the results of learning the image data at the same period showed high accuracy with an average of 93%, confirming that seasonal differences also affect learning.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1147-1158
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• 1998

Background: Portable cardiopulmonary bypass(CPB) technique has been used increasingly as a potent and effective option for emergency cardiopulmonary resuscitation(CPR) because it can maintain more stable hemodynamics and provide better survival than conventional CPR techniques. This study was designed to develop a prototype of Korean portable CPB system and, by applying it to CPR, to discriminate whether it would be superior to standard open-chest CPR. Material and Method: By using adult mongrel dogs, open-chest CPR(OCPR group, n=4) and portable-CPB CPR(CPB group, n=4) were compared with respects to restoration of spontaneous circulation(ROSC), hemodynamics, effects on blood cells, blood gas patterns, biochemical markers, and survivals. Ventricular fibrillation-cardiac arrest(VF-CA) of arrest(VF-CA) of 4 minutes followed by basic life support(BLS) of 15 minutes was applied in either group, which was standardized by the protocol of American Heart Association. Then, advanced life support(ALS) was applied to either group under the support of internal cardiac massage or CPB. ALS was maintained until ROSC was achieved but not longer than 30 minutes regardless of the presence of ROSC. All of the measured values were expressed as means±SD percent change from baseline. Result: During the early ALS, higher mean arterial pressure was maintained in CPB group than in OCPR group(90±19 vs. 71±32 %; p<.05) and lower mean pulmonary arterial pressure was also maintained in CPB group than in OCPR group(105±24 vs. 146±6%; p<.05). ROSC was achieved in all dogs. Post-ROSC levels of hematocrit, RBC, and platelet were decreased and plasma free hemoglobin was increased significantly in CPB group compared to OCPR group(p<.05). Changes in blood gas patterns, lactate, and CK-MB levels were not different between groups. Early mortality was seen in 3 dogs in OCPR group(survival time 31±36 hours) and 2 in CPB group(228±153 hours, p=ns). The remainders in both groups showed prolonged survival. Conclusion: These findings indicate that portable CPB can be effective to maintain stable hemodynamics during cardiac arrest, to achieve ROSC and to prolong survival. Further study is needed to refine the portable CPB system and to meet clinical challenges.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.3
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• pp.202-212
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• 2006

It is well-known that paclitaxel($Taxol^{(R)}$), which is extracted from the pacific and English yew, has been used as a chemotherapeutic agent for ovarian carcinoma and advanced breast carcinoma and Cyclosporin A, which is highly lipophilic cyclic peptide and isolated from a fungus, has been also used as an useful immunosuppressive drug after transplantation and is associated with cellular apoptosis. Since 1953, in which James Watson, Rosalind Franklin and Francis Crick discovered the double helical structure of DNA, a few kinds of techniques for identifying gene expression have been developed. In postgenomic period, many of researchers have used the DNA microarray which is high throughput screening technique to screen large numbers of gene expression simultaneously. In this study, we searched and screened the gene expression in the oral squamous cell carcinoma cell lines treated with $Taxol^{(R)}$, cyclosporin or cyclosporin combined with $Taxol^{(R)}$ using cDNA microarray. The results were as following; 1. It was useful that the appropriate concentration of Cyclosporin A and $Taxol^{(R)}$ used in oral squamous cell carcinoma cell line was under 1${\mu}g/ml$ and 3${\mu}g/ml$. 2. In the experimental group in which $Taxol^{(R)}$ and $Taxol^{(R)}$ + Cyclosporin A were used, the cell growth was extremely decreased. 3. In the group in which Cyclosporin A was used, the MTT assay was rarely decreased which means the activity of succinyl dehydrogenase is remained in mitochondria but in the group in which the mixture of Cyclosporin A and $Taxol^{(R)}$ were used, the MTT assay was extremely decreased. 4. In the each group in which Cyclosporin A(3 ${\mu}g/ml$) and $Taxol^{(R)}$(1 ${\mu}g/ml$) were used, the cell arrest was appeared in $G_2/M$ phase and in the group in which $Taxol^{(R)}$(3 ${\mu}g/ml$) was used, the cell arrest was appeared in both S phase and $G_2/M$ phase. 5. In the oral squamous cell carcinoma cell line treated with $Taxol^{(R)}$, several genes including ANGPTL4, RALBP1 and TXNRD1, associated with apoptosis, SUI1, MAC30, RRAGA and CTGF, related with cell growth, HUS1 and DUSP5, related with cell cycle and proliferation, ATF4 and CEBPG, associated with transcription factor, BTG1 and VEGF, associated with angiogenesis, FDPS, FCER1G, GPA33 and EPHA4 associated with signal transduction and receptor activity and AKR1C2 and UGTA10 related with carcinogenesis were detected in increased levels. The genes that showed increaced expression in the oral squamous cell carcinoma cell line treated with Cyclosporin A were CYR61, SERPINB2, SSR3 and UPA3A which are known as genes associated with cell growth, carcinogenesis, receptor activity and transcription factor. The genes expressed in the HN22 cell line treated with cyclosporin combined with $taxol^{(R)}$ were ALCAM and GTSE1 associated with cancer invasiveness and cell cycle regulation.

• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.247-259
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• 2000

This paper introduces a new technique that reduces the search times and Improves the accuracy of motion estimation using high temporal and spatial correlation of motion vector. Instead of using the fixed first search Point of previously proposed search algorithms, the proposed method finds more accurate first search point as to compensating searching area using high temporal and spatial correlation of motion vector. Therefore, the main idea of proposed method is to find first search point to improve the performance of motion estimation and reduce the search times. The proposed method utilizes the direction of the same coordinate block of the previous frame compared with a block of the current frame to use temporal correlation and the direction of the adjacent blocks of the current frame to use spatial correlation. Based on these directions, we compute the first search point. We search the motion vector in the middle of computed first search point with two fixed search patterns. Using that idea, an efficient adaptive predicted direction search algorithm (APDSA) for block matching motion estimation is proposed. In the experimental results show that the PSNR values are improved up to the 3.6dB as depend on the Image sequences and advanced about 1.7dB on an average. The results of the comparison show that the performance of the proposed APDSA algorithm is better than those of other fast search algorithms whether the image sequence contains fast or slow motion, and is similar to the performance of the FS (Full Search) algorithm. Simulation results also show that the performance of the APDSA scheme gives better subjective picture quality than the other fast search algorithms and is closer to that of the FS algorithm.

• Journal of Distribution Research
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• v.17 no.1
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• pp.37-63
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• 2012

In franchise business, exclusive sales territory (sometimes EST in table) protection is a very important issue from an economic, social and political point of view. It affects the growth and survival of both franchisor and franchisee and often raises issues of social and political conflicts. When franchisee is not familiar with related laws and regulations, franchisor has high chance to utilize it. Exclusive sales territory protection by the manufacturer and distributors (wholesalers or retailers) means sales area restriction by which only certain distributors have right to sell products or services. The distributor, who has been granted exclusive sales territories, can protect its own territory, whereas he may be prohibited from entering in other regions. Even though exclusive sales territory is a quite critical problem in franchise business, there is not much rigorous research about the reason, results, evaluation, and future direction based on empirical data. This paper tries to address this problem not only from logical and nomological validity, but from empirical validation. While we purse an empirical analysis, we take into account the difficulties of real data collection and statistical analysis techniques. We use a set of disclosure document data collected by Korea Fair Trade Commission, instead of conventional survey method which is usually criticized for its measurement error. Existing theories about exclusive sales territory can be summarized into two groups as shown in the table below. The first one is about the effectiveness of exclusive sales territory from both franchisor and franchisee point of view. In fact, output of exclusive sales territory can be positive for franchisors but negative for franchisees. Also, it can be positive in terms of sales but negative in terms of profit. Therefore, variables and viewpoints should be set properly. The other one is about the motive or reason why exclusive sales territory is protected. The reasons can be classified into four groups - industry characteristics, franchise systems characteristics, capability to maintain exclusive sales territory, and strategic decision. Within four groups of reasons, there are more specific variables and theories as below. Based on these theories, we develop nine hypotheses which are briefly shown in the last table below with the results. In order to validate the hypothesis, data is collected from government (FTC) homepage which is open source. The sample consists of 1,896 franchisors and it contains about three year operation data, from 2006 to 2008. Within the samples, 627 have exclusive sales territory protection policy and the one with exclusive sales territory policy is not evenly distributed over 19 representative industries. Additional data are also collected from another government agency homepage, like Statistics Korea. Also, we combine data from various secondary sources to create meaningful variables as shown in the table below. All variables are dichotomized by mean or median split if they are not inherently dichotomized by its definition, since each hypothesis is composed by multiple variables and there is no solid statistical technique to incorporate all these conditions to test the hypotheses. This paper uses a simple chi-square test because hypotheses and theories are built upon quite specific conditions such as industry type, economic condition, company history and various strategic purposes. It is almost impossible to find all those samples to satisfy them and it can't be manipulated in experimental settings. However, more advanced statistical techniques are very good on clean data without exogenous variables, but not good with real complex data. The chi-square test is applied in a way that samples are grouped into four with two criteria, whether they use exclusive sales territory protection or not, and whether they satisfy conditions of each hypothesis. So the proportion of sample franchisors which satisfy conditions and protect exclusive sales territory, does significantly exceed the proportion of samples that satisfy condition and do not protect. In fact, chi-square test is equivalent with the Poisson regression which allows more flexible application. As results, only three hypotheses are accepted. When attitude toward the risk is high so loyalty fee is determined according to sales performance, EST protection makes poor results as expected. And when franchisor protects EST in order to recruit franchisee easily, EST protection makes better results. Also, when EST protection is to improve the efficiency of franchise system as a whole, it shows better performances. High efficiency is achieved as EST prohibits the free riding of franchisee who exploits other's marketing efforts, and it encourages proper investments and distributes franchisee into multiple regions evenly. Other hypotheses are not supported in the results of significance testing. Exclusive sales territory should be protected from proper motives and administered for mutual benefits. Legal restrictions driven by the government agency like FTC could be misused and cause mis-understandings. So there need more careful monitoring on real practices and more rigorous studies by both academicians and practitioners.

• Journal of Intelligence and Information Systems
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• v.24 no.4
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• pp.219-240
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• 2018

Sentiment analysis, which is one of the text mining techniques, is a method for extracting subjective content embedded in text documents. Recently, the sentiment analysis methods have been widely used in many fields. As good examples, data-driven surveys are based on analyzing the subjectivity of text data posted by users and market researches are conducted by analyzing users' review posts to quantify users' reputation on a target product. The basic method of sentiment analysis is to use sentiment dictionary (or lexicon), a list of sentiment vocabularies with positive, neutral, or negative semantics. In general, the meaning of many sentiment words is likely to be different across domains. For example, a sentiment word, 'sad' indicates negative meaning in many fields but a movie. In order to perform accurate sentiment analysis, we need to build the sentiment dictionary for a given domain. However, such a method of building the sentiment lexicon is time-consuming and various sentiment vocabularies are not included without the use of general-purpose sentiment lexicon. In order to address this problem, several studies have been carried out to construct the sentiment lexicon suitable for a specific domain based on 'OPEN HANGUL' and 'SentiWordNet', which are general-purpose sentiment lexicons. However, OPEN HANGUL is no longer being serviced and SentiWordNet does not work well because of language difference in the process of converting Korean word into English word. There are restrictions on the use of such general-purpose sentiment lexicons as seed data for building the sentiment lexicon for a specific domain. In this article, we construct 'KNU Korean Sentiment Lexicon (KNU-KSL)', a new general-purpose Korean sentiment dictionary that is more advanced than existing general-purpose lexicons. The proposed dictionary, which is a list of domain-independent sentiment words such as 'thank you', 'worthy', and 'impressed', is built to quickly construct the sentiment dictionary for a target domain. Especially, it constructs sentiment vocabularies by analyzing the glosses contained in Standard Korean Language Dictionary (SKLD) by the following procedures: First, we propose a sentiment classification model based on Bidirectional Long Short-Term Memory (Bi-LSTM). Second, the proposed deep learning model automatically classifies each of glosses to either positive or negative meaning. Third, positive words and phrases are extracted from the glosses classified as positive meaning, while negative words and phrases are extracted from the glosses classified as negative meaning. Our experimental results show that the average accuracy of the proposed sentiment classification model is up to 89.45%. In addition, the sentiment dictionary is more extended using various external sources including SentiWordNet, SenticNet, Emotional Verbs, and Sentiment Lexicon 0603. Furthermore, we add sentiment information about frequently used coined words and emoticons that are used mainly on the Web. The KNU-KSL contains a total of 14,843 sentiment vocabularies, each of which is one of 1-grams, 2-grams, phrases, and sentence patterns. Unlike existing sentiment dictionaries, it is composed of words that are not affected by particular domains. The recent trend on sentiment analysis is to use deep learning technique without sentiment dictionaries. The importance of developing sentiment dictionaries is declined gradually. However, one of recent studies shows that the words in the sentiment dictionary can be used as features of deep learning models, resulting in the sentiment analysis performed with higher accuracy (Teng, Z., 2016). This result indicates that the sentiment dictionary is used not only for sentiment analysis but also as features of deep learning models for improving accuracy. The proposed dictionary can be used as a basic data for constructing the sentiment lexicon of a particular domain and as features of deep learning models. It is also useful to automatically and quickly build large training sets for deep learning models.