• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.4
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• pp.269-275
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• 2013

Recently, importance of pedestrian road network is getting emphasized as it is possible to provide mobile device users with both route guidance services and surrounding spatial information. However, it costs a tremendous amount of budget for generating and renovating pedestrian road network nationally, which hinder further advances of these services. Hence, algorithms extracting pedestrian road network automatically based on raster data are needed. On the other hand, road dataset generated from raster data usually has unnecessary vertices which lead to maintenance disutility such as excessive turns and increase in data memory. Therefore, this study proposed a method of selecting a proper threshold automatically for separate road entity using not only Douglas-Peucker algorithm but also road attribute data of digital map in order to remove redundant vertices, which maximizes line simplification efficiency and minimizes distortion of shape of roads simultaneously. As a result of the test, proposed method was suitable for automatic line simplification in terms of reduction ratio of vertices and accuracy of position.

• Journal of Gifted/Talented Education
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• v.14 no.4
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• pp.47-70
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• 2004

We analyzed the validity of Science Highschool's selection process for the students from Science Gifted Education Center in order to suggest the direction of improvement. First of all, we invested the students' achievement in Mathematics and Science. As a result, we found that the students are not so good at mathematics and science through the selection process for the students from Science Gifted Education Center. However the difference is not statistically meaningful. On the contrary, The achievement of the students from Science Gifted Education Center is above average who were selected through the other course, e. g. the students who acquired the recommendation of principal, winner of prize in Olympiad of Mathematics or Science. We didn't find any meaningful result in the investigation of Affective Domain in Science. And then we found that the students prefer the generous environment through the selection process for the students from Science Gifted Education Center. As a whole, the selection process for the students from Science Gifted Education Center was not so satisfying. It should be reformed; we should examine the students' portfolio on the activities in the Science Gifted Education Center, and the entrance examination should include both divergent and convergent problems to find out the students' creativity. And the 3 dimensional process is also essential through the multiple steps.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.29-39
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• 2021

As damages to individuals, private sectors, and businesses increase due to newly occurring cyber attacks, the underlying network security problem has emerged as a major problem in computer systems. Therefore, NIDS using machine learning and deep learning is being studied to improve the limitations that occur in the existing Network Intrusion Detection System. In this study, a deep learning-based NIDS model study is conducted using the Convolution Neural Network (CNN) algorithm. For the image classification-based CNN algorithm learning, a discrete algorithm for continuity variables was added in the preprocessing stage used previously, and the predicted variables were expressed in a linear relationship and converted into easy-to-interpret data. Finally, the network packet processed through the above process is mapped to a square matrix structure and converted into a pixel image. For the performance evaluation of the proposed model, NSL-KDD, a representative network packet data, was used, and accuracy, precision, recall, and f1-score were used as performance indicators. As a result of the experiment, the proposed model showed the highest performance with an accuracy of 85%, and the harmonic mean (F1-Score) of the R2L class with a small number of training samples was 71%, showing very good performance compared to other models.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.4
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• pp.827-839
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• 2012

A cell phone is very close to the user and therefore should be considered in digital forensic investigation. Recently, the proportion of smartphone owners is increasing dramatically. Unlike the feature phone, users can utilize various mobile application in smartphone because it has high-performance operating system (e.g., Android, iOS). As acquisition and analysis of user data in smartphone are more important in digital forensic purposes, smartphone forensics has been studied actively. There are two way to do smartphone forensics. The first way is to extract user's data using the backup and debugging function of smartphones. The second way is to get root permission, and acquire the image of flash memory. And then, it is possible to reconstruct the filesystem, such as YAFFS, EXT, RFS, HFS+ and analyze it. However, this methods are not suitable to recovery and analyze deleted data from smartphones. This paper introduces analysis techniques for fragmented flash memory pages in smartphones. Especially, this paper demonstrates analysis techniques on the image that reconstruction of filesystem is impossible because the spare area of flash memory pages does not exist and the pages in unallocated area of filesystem.

• Korean Journal of Culture and Social Issue
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• v.24 no.4
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• pp.541-562
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• 2018

Conflict of interest (COI) is one of the dominant circumstantial factors of moral corruption across various fields. Several management strategies have been proposed to prevent self-interested decision making in COIs. Among these strategies, message persuasion has been considered as a practical and effective approach. Prior studies have found that framing and repetition are two of the major factors in the persuasion effect of message. However, their effect on moral decision making in COI has not been well explored. The purpose of this study was to compare the differential effects of positively framed message and negatively framed message, and secondly, to investigate how the effectiveness of persuasive message changes through repetitive exposures. A total of 63 participants were randomly assigned to one of 3 framing conditions: positive framing, negative framing, and no-message condition. Prior to the on-line experiment involving a consultation task, differently framed persuasive message were presented to the participants. This process was repeated four times in a row. The results showed that participants with positive-framing message were less likely to provide self-interested consultation than participants in the no-message condition. Also, a U-shaped quadric relation between repetition and self-interest consultation was found. Implications and limitations are further discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.261-261
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• 2016

플래시 메모리 (flash memory)는 DRAM(dynamic racdom access memory)이나 SRAM(static random access memory)에 비해 소자의 구조가 매우 단순하기 때문에 집적도가 높아서 기기의 소형화가 가능하다는 점과 제조비용이 낮다는 장점을 가지고 있다. 또한, 전원을 차단하면 정보가 사라지는 DRAM이나 SRAM과 달리 전원이 꺼지더라도 저장된 정보가 지워지지 않는다는 특징을 가지고 있어서 ROM(read only memory)과 정보의 입출력이 자유로운 RAM의 장점을 동시에 가지기 때문에 활용도가 크다. 또한, 속도가 빠르고 소비전력이 작아서 USB 드라이브, 디지털 TV, 디지털 캠코더, 디지털 카메라, 휴대전화, 개인용 휴대단말기, 게임기 및 MP3 플레이어 등에 널리 사용되고 있다. 특히, 낸드(NAND)형의 플래시 메모리는 고집적이 가능하며 하드디스크를 대체할 수 있어 고집적 음성이나 화상 등의 저장용으로 많이 쓰이며 일정량의 정보를 저장해두고 작업해야 하는 휴대형 기기에도 적합하며 가격도 노어(NOR)형에 비해 저렴하다는 장점을 가진다. 최근에는 smart watch, wearable device 등과 같은 차세대 디스플레이 소자에 대한 관심이 증가함에 따라 투명하고 유연한 메모리 소자에 대한 연구가 다양하게 진행되고 있으며 유리나 플라스틱과 같은 기판 위에서 투명한 플래시 메모리를 형성하는 기술에 대한 관심이 높아지고 있다. 전하트랩형 (charge trap type) 플래시 메모리는 플로팅 게이트형 플래시 메모리와는 다르게 정보를 절연막 층에 저장하므로 인접 셀간의 간섭이나 소자의 크기를 줄일 수 있기 때문에 투명하고 유연한 메모리 소자에 적용이 가능한 차세대 플래시 메모리로 기대되고 있다. 전하트랩형 플래시메모리는 정보를 저장하기 위하여 tunneling layer, trap layer, blocking layer의 3층으로 이루어진 게이트 절연막을 가진다. 전하트랩 플래시 메모리는 게이트 전압에 따라서 채널의 전자가 tunnel layer를 통해 trap layer에 주입되어 정보를 기억하게 되는데, trap layer에 주입된 전자가 다시 채널로 빠져나가는 charge loss 현상이 큰 문제점으로 지적된다. 따라서 tunnel layer의 막질향상을 위한 다양한 열처리 방법들이 제시되고 있으며, 기존의 CTA (conventional thermal annealing) 방식은 상대적으로 높은 온도와 긴 열처리 시간을 가지고, RTA (rapid thermal annealing) 방식은 매우 높은 열처리 온도를 필요로 하기 때문에 플라스틱, 유리와 같은 다양한 기판에 적용이 어렵다. 따라서 본 연구에서는 기존의 열처리 방식보다 에너지 전달 효율이 높고, 저온공정 및 열처리 시간을 단축시킬 수 있는 마이크로웨이브 열처리(microwave irradiation, MWI)를 도입하였다. Tunneling layer, trap layer, blocking layer를 가지는 MOS capacitor 구조의 전하트랩형 플래시 메모리를 제작하여 CTA, RTA, MWI 처리를 실시한 다음, 전기적 특성을 평가하였다. 그 결과, 마이크로웨이브 열처리를 실시한 메모리 소자는 CTA 처리한 소자와 거의 동등한 정도의 우수한 전기적인 특성을 나타내는 것을 확인하였다. 따라서, MWI를 이용하면 tunnel layer의 막질을 향상시킬 뿐만 아니라, thermal budget을 크게 줄일 수 있어 차세대 투명하고 유연한 메모리 소자 제작에 큰 기여를 할 것으로 예상한다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.5 s.311
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• pp.79-87
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• 2006

In this study, we evaluated the performance of a companding strategy as a preprocessing for speech enhancement and noise reduction. The proposed algorithm is based on two tone suppression that is human's hearing characteristics. This algorithm enhances spectral peak of speech signal and reduces background noise, however it has tradeoff characteristics between speech distortion and noise reduction due to limited channel number and nonlinear block. Therefore, we designed two different companding structures that have relative characteristics of noise reduction and speech distortion and found suitable companding structures by difference of individual speech perception ability in noise environment. Thus we proposed speech perception enhancement of cochlear implant user in noise environment with low SNR. The performance of the proposed algorithm was evaluated through 5 normal hearing listeners using noise band simulation. Improvement of speech perception was observed for all subjects and each subject preferred the different type of companding structure.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.18-25
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• 2005

Traumatic bone cyst is a nonodontogenic cyst without epithelial-linig which contains fluid in it's cavity, and it is limited by bone walls with no evidence of infection. Traumatic bone cyst is asymptomatic and appears more frequently in the second decade. Gender distribution is approximately equal, although males are affected slightly often than females. Radiographically the lesion shows a well demarcated radiolucent lesion of variable size and the lesion may have scalloped margins. The adjacent teeth to traumatic bone cyst remains vital. Traumatic bone cyst is usually treated by surgical exploration and currettage of the lesion. In the first case of this case report, the patient was refered from the local dental clinic for the radiolucent area under the left mandibular first molar. From the panorama radiograph at the first visit, the radiolucent area of the left mandible showed a well defined scalloped margin and identified as traumatic bone cyst. In the second case, the patient have visited for the chief complaint of swelling and abcess of right maxillary second premolar. In the radiographic check up with panorama radiograph, the radiolucent lesion with well demarcated scalloped margin was found in the right mandible body, and identified as traumatic bone cyst. In the first case, overinstrumentation was done through the mesial root canal to irrigate the lesion. In the second case, not any treatment was done, and watched the progression of the lesion. And in both cases, after two month, the radiolucency and the size of the lesion has decreased to show healing in progress.

• Journal of Digital Contents Society
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• v.10 no.4
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• pp.493-499
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• 2009

Three methods frequently used for Hangul display in computer systems are Standard Johab Code in which each of Hangul consonants and vowels is given a 5-bit code and each syllable created by combining them forms a 2-byte code, Standard Wansung Code in which each of all the syllables generally used for Hangul presentation forms a 2-byte code, and Unicode in which each syllable in most of the world's language systems is given a unique code so that it allows computers to consistently represent and manipulate them in a unified manner. An embedded system in general has a lower processing power and a limited amount of storage space, compared to a personal compute(PC) system. According to its usage, however, the former may have a processing power equal to that of the latter. Hence, when Hangul display needs to be adopted, an embedded system must choose a display method suitable for its own resource environment. This paper introduces a TFT LCD initialization method and pixel display functions of an LN2440SBC embedded board on which an LP35, a 3.5" TFT LCD kit, is attached. Using the initialization and pixel display functions, in addition, we compare three aforementioned Hangul display methods, in terms of their processing speeds and amounts of memory space required. According to experiments, Standard Johab Code requires less amount of memory space but more processing time than Standard Wansung Code, and Unicode requires the largest amount of memory space but the least processing time.

• KSBB Journal
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• v.22 no.4
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• pp.234-238
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• 2007

We used electrospary ionization ion trap tandem mass spectrometry (ESI-IT tandem MS) to structural elucidation of three different biantennary-type glycans having zero, one, two galactoses (G0, G1, G2). The highest fragment ion in the MS/MS spectra of three glycans was produced by 0,2-ring cleavage of fucose-linked N-acetylglucosamine (GlcNAc) in reducing end. The fragment ions both from precursor ions and 0,2-ring cleaved ions ($^{0.2}An$; n=5 for G0, n=6 for G1 and G2) were not overlapped each other. As results of $MS^n$ analyses, tandem fragmentation trees of each glycans were generated and 2,4-ring cleavages ($^{2.4}A_6$) were occurred in GlcNAc linked to reducing end GlcNAc. This structural elucidation and fragmentation study of N-linked glycans by tandem mass spectrometry can be applied to structural analysis of more complicated glycans.