• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.581-586
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• 2023

Recently a drama that features a lawyer with autism spectrum disorder has attracted a lot of attention, raising interest in the difficulties faced by people with autism spectrum disorders. If the Autism spectrum gets detected early and proper education and treatment, the prognosis can be improved, so the development of the treatment is urgently needed. Drugs currently used to treat autism spectrum often have side effects, so Digital Therapeutics that have no side effects and can be supplied in large quantities are drawing attention. In this paper, we introduce 'AEmotion', an application and a Digital Therapeutic that provides emotion and facial expression learning for toddlers with an autism spectrum disorder. This system is developed as an application for smartphones to increase interest in training autistic children and to test easily. Using machine learning, this system consists of three main stages: an 'emotion learning' step to learn emotions with facial expression cards, an 'emotion identification' step to check if the user understood emotions and facial expressions properly, and an 'expression training' step to make appropriate facial expressions. Through this system, it is expected that it will help autistic toddlers who have difficulties with social interactions by having problems recognizing facial expressions and emotions.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.9
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• pp.283-290
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• 2023

With the recent steady development of IoT technology, it is widely used in medical systems and smart TV watches. 66% of software development is developed through language C, which is vulnerable to memory attacks, and acts as a threat to IoT devices using language C. A stack-smashing overflow attack inserts a value larger than the user-defined buffer size, overwriting the area where the return address is stored, preventing the program from operating normally. IoT devices with low memory capacity are vulnerable to stack smashing overflow attacks. In addition, if the existing vaccine program is applied as it is, the IoT device will not operate normally. In order to defend against stack smashing overflow attacks on IoT devices, we used canaries among several detection methods to set conditions with random values, checksum, and DSLR (random storage locations), respectively. Two canaries were placed within the buffer, one in front of the return address, which is the end of the buffer, and the other was stored in a random location in-buffer. This makes it difficult for an attacker to guess the location of a canary stored in a fixed location by storing the canary in a random location because it is easy for an attacker to predict its location. After executing the detection program, after a stack smashing overflow attack occurs, if each condition is satisfied, the program is terminated. The set conditions were combined to create a number of eight cases and tested. Through this, it was found that it is more efficient to use a detection method using DSLR than a detection method using multiple conditions for IoT devices.

• Journal of KIISE:Software and Applications
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• v.37 no.7
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• pp.548-557
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• 2010

In this paper, we propose a semi-automatic modeling approach of ontology to annotate VOD to realize the IPTV's intelligent searching. The ontology is made by combining partial tree that extracts hypernym, hyponym, and synonym of keywords related to a service domain from WordNet. Further, we add to the partial tree new keywords that are undefined in WordNet, such as foreign words and words written in Chinese characters. The ontology consists of two parts: generic hierarchy and specific hierarchy. The former is the semantic model of vocabularies such as keywords and contents of keywords. They are defined as classes including property restrictions in the ontology. The latter is generated using the reasoning technique by inferring contents of keywords based on the generic hierarchy. An annotation generates metadata (i.e., contents and genre) of VOD based on the specific hierarchy. The generic hierarchy can be applied to other domains, and the specific hierarchy helps modeling the ontology to fit the service domain. This approach is proved as good to generate metadata independent of any specific domain. As a result, the proposed method produced around 82% precision with 2,400 VOD annotation test data.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.3
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• pp.15-23
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• 2009

In ubiquitous environments, invisible devices and software are connected to one another to provide convenient services to users. In this environments, users want to get a variety of customized services by using only an individual mobile device which has limitations such as tiny display screens, limited input, and less powerful processors. Therefore, The device sharing for solving these limitation problems and its efficient processing is one of the new research topics. This paper proposes a device recommender system which searches and recommends devices for composing user requested services. The device recommender system infers devices based on environmental context of a user. However, customized devices for each user are different because of a variety of user preference even if users want to get the same service in the same space, Therefore the paper considers the user preference for device recommendation. Our device recommender system is implemented and tested on the real mobile object developed for device sharing in ubiquitous environments. Therefore we can expect that the system will be adaptable in real device sharing environments.

• Journal of the Korea Society of Computer and Information
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• v.25 no.1
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• pp.71-77
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• 2020

In this paper, we propose a method in which PingPong256 combines LFSR and variable clock to generate an irregular PRNG and use it for image encryption. PingPong256 is guaranteed an extended period based on the two LFSRs, and the variable clock is a structure that outputs the result of operating a predetermined clock in one operation by referring to the state of the different LFSR. A variable clock is characterized by the difficulty of predicting the output at any time because the choice increases with time. PingPong256 combines the advantages of LFSR and variable clock, the convenience of hardware and software implementation, and the benefits of sensitivity and irregular periods. Also, the statistical safety was verified using the NIST SP800-22, the safety of the proposed method, and the sensitivity of the image change was tested using NPCR and UACI.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.11
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• pp.471-478
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• 2014

Database replication is utilized to increase credibility, availability and prevent overload of distributed databases. Two models currently exist for replication - Master/Slave and Multi-Master. Since the Multi-Master model has problems of increasing complexity and costs to interface among multiple databases for updates and inserts, the Master/Slave model is more appropriate when frequent data inserts and updates are required. However, Master/Slave model also has a problem of not having exact criteria when systems choose to connect between Master and Slave for transactions. Therefore, this research suggests a routing algorithm based on AOP (Aspect Oriented Programming) in the Master/Slave database model. The algorithm classifies applications as cross-cutting concerns based on AOP, modularizes each concern, and routes transactions among Master and Slave databases. This paper evaluates stability and performance of the suggested algorithm through integration tests based on scenarios.

• The Journal of Korean Association of Computer Education
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• v.23 no.3
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• pp.41-47
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• 2020

Computational Thinking(CT) is drawing attention as a core competency required for future talent in the 21st century. Software education for improving CT ability at home and abroad is in full swing. Among them, problem-solving programming education helps to improve CT ability. The CT-TDPS learning model follows the decomposition, abstraction thinking process, which modularizes complex problems, and the Agile development method, which is an iterative and incremental programming method to implement it. In this study, we tried to confirm the improvement of CT ability by applying CT-TDPS learning model to problem solving programming education using Scratch. As a result of the study, it was confirmed that in the problem solving programming education using the CT-TDPS learning model, it improved in all aspects of computing concept, computing performance, and computing perspective, which are sub-factors of CT ability. In addition, it was confirmed that there was a significant difference in the experimental group as a result of the t-test on the Dr.Scratch automatic evaluation result.

• Journal of KIISE:Software and Applications
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• v.36 no.6
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• pp.479-490
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• 2009

A number of temporal abstraction approaches have been suggested so far to handle the high computational complexity of Markov decision problems (MDPs). Although the structure of temporal abstraction can significantly affect the efficiency of solving the MDP, to our knowledge none of current temporal abstraction approaches explicitly consider the relationship between topology and efficiency. In this paper, we first show that a topological measurement from complex network literature, mean geodesic distance, can reflect the efficiency of solving MDP. Based on this, we build an incremental method to systematically build temporal abstractions using a network model that guarantees a small mean geodesic distance. We test our algorithm on a realistic 3D game environment, and experimental results show that our model has subpolynomial growth of mean geodesic distance according to problem size, which enables efficient solving of resulting MDP.

• Journal of KIISE:Software and Applications
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• v.30 no.5_6
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• pp.550-558
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• 2003

Context-aware application plays an important role in ubiquitous computing (ubiComp) environment by providing user with anytime, anywhere services even without any explicitly triggered command. In this paper we propose a unified context-aware application model which is an essential part to develop various applications in ubiquitous computing environment. The proposed model affirms the independence between sensor and application by using unified context in the form of 5W1H. It also ensures that application exploits relatively accurate context to trigger personalized services. To show usefulness of the proposed model, we apply it to the sensors and applications in the ubiHome, a test bed for ubiComp-enabled home applications. According to the experimental results, without loss of generality, we believe it can be extended to various context-aware applications in daily life.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.80-80
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• 2003

디지털 의료영상 획득기술과 컴퓨터 및 네트워크 기술의 발달로 현재 각 병원에서는 PACS(Picture Archiving and Communication System)를 설치하여 필름을 사용하지 않고 진단과 진료를 하는 병원이 증가하고 있으며, 이에 따라 기존 필름상태의 의료영상은 필름디지타이저로 디지털 영상화한 후 모니터를 통하여 판독과 진료에 이용하고 있다. 본 연구에서는 현재 세브란스병원에서 사용되고 있는 CCD 방식 필름디지타이저와 레이저 스캐너방식 필름디지타이저의 픽셀값 균일도에 대해 중점적으로 비교, 분석하고자 한다. 픽셀값 균일도 측정을 위해 필름프린터를 이용하여 균일한 광학밀도를 가진 필름을 출력하였다. 그 테스트 필름은 각 사분면에 각기 다른 광학밀도를 가지고 있었으며, 그 광학밀도 값은 각각 0.19, 0.71, 1.41, 그리고 3.10 이었다. 제작된 필름은 레이저 (Model 2905, Array Corp., Japan) 방식과 CCD 방식 (SEDAS Media Film Scanner, Kodak, japan) 디지타이저에 의해 디지털화 되었다. 그 영상들은 다시 분석을 위해 PACS를 통해 PC로 전송되어졌고 자체 제작된 소프트웨어를 이용하여 균일도에 대한 분석을 수행하였다. 하나의 사분면 영상에 대하여 일정한 간격과 크기로 20개의 ROI를 만들고, 그 내부의 픽셀값들의 평균값을 구하여 그 영역의 대푯값으로 하였다. 그 대푯값들 중 최대값과 최소값의 차이에 대한 백분율로써 균일도를 표시하였다. 그 결과 광학밀도가 0.19인 사분변의 영상에서의 균일도는 레이저 방식 및 CCD 방식 각각에서 99.8%, 94.3%였으며, 0.71인 사분면에서는 99.4%, 75.6%, 1.41 일때는 97.9%, 62.96%, 그리고 3.1인 사분면에서는 82.7%, 53.7%였다. 같은 광학밀도를 가진 사분면에서는 레이저방식의 균일도가 CCD 방식에 비해 더 우수함을 알 수 있었으며, 같은 방식에서 얻은 영상이라 할지라도 광학 밀도값이 높은 사분변에서 얻은 영상일수록 균일도가 떨어짐을 알 수 있었다. 결론적으로, 레이저 방식 필름 디지타이저는 균일도 면에서도 CCD 방식에 비해 우수함을 알 수 있었으며 CCD 방식은 백라이트의 균일도가 영상의 균일도에 영향을 미칠수도 있는 만큼 향후 거기에 대한 연구도 이루어져야 할 것으로 생각된다.