• The Transactions of the Korea Information Processing Society
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• v.13 no.5
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• pp.221-226
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• 2024

In information retrieval, queries come in various types, ranging from abstract queries to those containing specific keywords, making it a challenging task to accurately produce results according to user demands. Additionally, search systems must handle queries encompassing various elements such as typos, multilingualism, and codes. Reranking is performed through training suitable documents for queries using DeBERTa, a deep learning model that has shown high performance in recent research. To evaluate the effectiveness of the proposed method, experiments were conducted using the test collection of the Product Search Track at the TREC 2023 international information retrieval evaluation competition. In the comparison of NDCG performance measurements regarding the experimental results, the proposed method showed a 10.48% improvement over BM25, a basic information retrieval model, in terms of search through query error handling, provisional relevance feedback-based product title-based query expansion, and reranking according to query types, achieving a score of 0.7810.

• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.87-94
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• 2020

Social reviews such as SNS feeds and blog articles have been widely used to extract keywords reflecting opinions and complaints from users' perspective, and often include proper nouns or new words reflecting recent trends. In general, these words are not included in a dictionary, so conventional morphological analyzers may not detect and extract those words from the reviews properly. In addition, due to their high processing time, it is inadequate to provide analysis results in a timely manner. This paper presents a method for efficient keyword extraction from social reviews based on the notion of cohesion scoring. Cohesion scores can be calculated based on word frequencies, so keyword extraction can be performed without a dictionary when using it. On the other hand, their accuracy can be degraded when input data with poor spacing is given. Regarding this, an algorithm is presented which improves the existing cohesion scoring mechanism using the structure of a word tree. Our experiment results show that it took only 0.008 seconds to extract keywords from 1,000 reviews in the proposed method while resulting in 15.5% error ratio which is better than the existing morphological analyzers.

• Journal of the Korea Society of Computer and Information
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• v.19 no.3
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• pp.63-71
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• 2014

We analyze the execution time of Reed-Solomon coding, which is the MAC-layer forward error correction scheme used in CDMA2000 1xEV-DO broadcast services, under different air channel conditions. The results show that the time constraints of MPEG-4 cannot be guaranteed by Reed-Solomon decoding when the packet loss rate (PLR) is high, due to its long computation time on current hardware. To alleviate this problem, we propose three error control schemes. Our static scheme bypasses Reed-Solomon decoding at the mobile node to satisfy the MPEG-4 time constraint when the PLR exceeds a given boundary. Second, dynamic scheme corrects errors in a best-effort manner within the time constraint, instead of giving up altogether when the PLR is high; this achieves a further quality improvement. The third, video-aware dynamic scheme fixes errors in a similar way to the dynamic scheme, but in a priority-driven manner which makes the video appear smoother. Extensive simulation results show the effectiveness of our schemes compared to the original FEC scheme.

• Journal of the Korea Society of Computer and Information
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• v.14 no.5
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• pp.65-75
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• 2009

The development of IT technology, Internet popularity is increasing geometrically. However, as its side effect, the intrusion behaviors such as information leakage for key system and infringement of computation network etc are also increasing fast. The attack traffic detection method which is suggested in this study utilizes the Snort, traditional NIDS, filters the packet with false positive among the detected attack traffics using Nmap information. Then, it performs the secondary filtering using nessus vulnerability information and finally performs correlation analysis considering appropriateness of management system, severity of signature and security hole so that it could reduce false positive alarm message as well as minimize the errors from false positive and as a result, it raised the overall attack detection results.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.479-482
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• 2010

실시간 영상에서 객체 추적은 수년간 컴퓨터 비전 및 여러 실용적 응용 분야에서 관심을 가지는 주제 중 하나이다. 하지만 배경영상의 잡음을 객체로 인식하는 오류로 인하여 추출하고자 하는 객체를 찾지 못하는 경우가 있다. 본 논문에서는 실시간 영상에서 적응적 배경영상을 이용하여 객체를 추출하고 추적하는 방법을 제안한다. 입력되는 영상에서 배경영역의 잡음을 제거하고 조명에 강인한 객체 추출을 위하여 객체영역이 아닌 배경영역 부분을 실시간으로 갱신함으로써 적응적 배경영상을 생성한다. 그리고 배경영상과 카메라로부터 입력되는 입력영상과의 차를 이용하여 객체를 추출한다. 추출된 객체의 내부점을 이용하여 최소 사각영역을 설정하고, 이를 통해 객체를 추적한다. 아울러 제안방법의 성능에 대한 실험결과를 기존 추적 알고리즘과 비교, 분석하여 평가한다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.109-116
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• 2010

Due to the increasing interest and demands of user privacy, remote user authentication schemes using smart card has been researched in active. Recently, a lot of suggestion have been made in order to provide user's anonymity and trace a malicious user. In 2008, Kim et al. proposed a traceable anonymity authentication scheme. In 2009, Choi et al. pointed out that Kim's protocol was insecure against outsider attacker and proposed an improved scheme. But Kim's and Choi's schemes fail to provide the user's anonymity or compute some values in the protocol. In this paper, we analyse those problems and suggest two improved schemes to resolve those problems.

• The Journal of Korean Association of Computer Education
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• v.16 no.4
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• pp.33-45
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• 2013

This paper aims at exploring how a high school student is engaged with C computer programming language and explore deep aspects of programming experiences based on video recalled interview as part of portraiture. The single case was selected and several in-depth interviews and video recording were arranged after Oct 2011. The portrait of K reveals interesting strands of his computer programming experiences with his own thinking patterns and exploring ideas for more concrete ways of coding his thinking similar to scientific experiments; ie, design-development-implementation-debugging-revision. Overall, this case illustrates how the inner aspects of subjective programming experiences on the tower of Hanoi were integrated and unified within himself for inner growth. We discussed the student's inner faculties as part of the student's unity and suggested future research direction.

• The Journal of Korean Association of Computer Education
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• v.20 no.4
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• pp.27-36
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• 2017

The purpose of this study is to design and implement an instructional model for flipped learning of programming class. Because a programming process requires a high level of abstract thinking with a good understanding of a programming language, many students have difficulty in programming. For this characteristic of programming, it is not easy to effectively achieve learning goals of programming lesson by lecturing grammatical elements of a programming language and the following examples in a limited class time. In order to overcome these problems and to make effective programming lessons, we designed an instructional model based on flipped learning. Especially, in this study, we analyzed learners' difficulties in programming learning and errors that occurred in actual programming process for designing the instructional model. As a result of applying this model to the class, it was found that the students were generally satisfied with the lesson by having positive communication with other students in the classroom and actively participating in the learning.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.3
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• pp.91-98
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• 2021

Today's information and communication technology is rapidly developing, the security of IT infrastructure is becoming more important, and at the same time, cyber attacks of various forms are becoming more advanced and sophisticated like intelligent persistent attacks (Advanced Persistent Threat). Early defense or prediction of increasingly sophisticated cyber attacks is extremely important, and in many cases, the analysis of network-based intrusion detection systems (NIDS) related data alone cannot prevent rapidly changing cyber attacks. Therefore, we are currently using data generated by intrusion detection systems to protect against cyber attacks described above through Host-based Intrusion Detection System (HIDS) data analysis. In this paper, we conducted a comparative study on machine learning algorithms using LID-DS (Leipzig Intrusion Detection-Data Set) host-based intrusion detection data including thread information, metadata, and buffer data missing from previously used data sets. The algorithms used were Decision Tree, Naive Bayes, MLP (Multi-Layer Perceptron), Logistic Regression, LSTM (Long Short-Term Memory model), and RNN (Recurrent Neural Network). Accuracy, accuracy, recall, F1-Score indicators and error rates were measured for evaluation. As a result, the LSTM algorithm had the highest accuracy.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.61-69
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• 2012

This paper shows results of the precise time comparison technique based on GPS code transfer in order to determine the UTC(Universal Time Coordinated) and generate TAI(International Atomic Time). CGGTTS(CCTF Group on GNSS Time Transfer Standards) which is generated by GPS timing receivers is used as the international standard format. For geodetic receivers which provide RINEX formats as GPS time transfer results, ROB(Royal Observatory of Belgium) developed a conversion program, r2cggtts, and have distributed the program to timing laboratories participating in TAI link all over the world. Timing laboratories generate the time comparison results of GPS code transfer by the program and send them to BIPM(Bureau International des Poids et Mesures) periodically. In this paper, we introduce the delay features generated while GPS code is transferred and the calibration methods of them. Then, we introduce the tropospheric delay and analyze the results of Saastamoinen model and NATO(North Atlantic Treaty organization) model. Saastamoinen model is the representative tropospheric zenith path delay model and NATO model is applied to the legacy r2cggtts program.