• Journal of information and communication convergence engineering
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• 제20권4호
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• pp.250-258
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• 2022

The emerging scope of the Internet-of-Things (IoT) has piqued the interest of industry and academia in recent times. Therefore, security becomes the main issue to prevent the possibility of cyberattacks. Jamming attacks are threads that can affect performance and cause significant problems for IoT device. This study explores a smart jamming attack (coalition attack) in which the attackers were previously a part of the legitimate network and are now back to attack it based on the gained knowledge. These attackers regroup into a coalition and begin exchanging information about the legitimate network to launch attacks based on the gained knowledge. Our system enables jammer nodes to select the optimal transmission rates for attacks based on the attack probability table, which contains the most probable link transmission rate between nodes in the legitimate network. The table is updated constantly throughout the life cycle of the coalition. The simulation results show that a coalition of jammers can cause highly successful attacks.

• 기술혁신연구
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• 제16권1호
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• pp.81-106
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• 2008

By analyzing a nation-wide survey, this article examines research related norms and values of 684 scientists in 16 universities and 7 government supported research institutes. The survey shows that Korean scientific community tends to reject communality and disinterestedness while it accepts universalism as a norm. Organized skepticism is received a lukewarm support. In contrast, Korean scientific community tends to perceive the intellectual property and secrecy as legitimate and believe that scientists should consider the applicability of scientific research outcome and its social impacts when they choose research topics. When other variables are controlled for, the more basic research a scientist conducts the scientist is more likely to support communality and reject secrecy. The younger scientists are less likely to accept disinterestedness and the claim that the scientists should keep distance from social issues than the older. Scientists who work in the government-supported research institutes are more likely to view secrecy for more than 6 months as legitimate and reject the claim that science should not be affected by society than university scientists. The implications of these findings are discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.4223-4249
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• 2015

A novel jamming detection technique to detect the presence of jamming in the downstream direction for cluster based wireless sensor networks is proposed in this paper. The proposed technique is deployed in base station and in cluster heads. The proposed technique is novel in two aspects: Firstly, whenever a cluster head receives a packet it verifies whether the source node is legitimate node or new node. Secondly if a source node is declared as new node in the first step, then this technique observes the behavior of the new node to find whether the new node is legitimate node or jammed node. In order to monitor the behavior of the existing node and new node, the second step uses two metrics namely packet delivery ratio (PDR) and received signal strength indicator (RSSI). The rationality of using PDR and RSSI is presented by performing statistical test. PDR and RSSI of every member in the cluster is measured and assessed by the cluster head. And finally the cluster head determines whether the members of the cluster are jammed or not. The CH can detect the presence of jamming in the cluster at member level. The base station can detect the presence of jamming in the wireless sensor network at CH level. The simulation result shows that the proposed technique performs extremely well and achieves jamming detection rate as high as 99.85%.

• 한국정보전자통신기술학회논문지
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• 제4권4호
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• pp.311-317
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• 2011

최근 유비쿼터스 환경에서 바코드 대신 RFID가 대치되었지만, RFID 는 무선 주파수를 사용하기 때문에 프라이버시와 보안성에 많은 문제점을 가지고 있다. 첫째는 비인가 리드가 임의 RFID 태그의 ID 정보를 쉽게 읽어 들일 수 있고, 둘째는 공격자가 수집한 태그 ID 정보를 이용하여 합법적인 리더에게 인가된 태그인 것처럼 쉽게 속일 수 있다. 본 논문에서는 SSG 기반 개선된 RFID 인증 프로토콜을 제안하였다. SSG 알고리즘은 LFSR 과 선택로직만으로 구성되어 있다. 따라서 RFID 태그와 같은 극히 제한적인 자원을 갖는 시스템에서 하드웨어 구현이 가능하며, 출력 비트 스트림은 의사난수로 사용함으로써 다양한 공격에 안전하다. 제안한 프로토콜은 SSG를 기반으로 하기 때문에 안전하고 효율적이다.

• 무역상무연구
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• 제17권
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• pp.129-146
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• 2002

The electronic technology development have occurred in the face of existing legal barriers to legal efficacy of computer information goods, and the liberating promise of electronic transactions cannot fully realized unless there is predictability in the legal rules that govern such transactions. This study analyzes some theoretical fundamentals of the Act. First, it proposes that the Act clarify and set forth uniform legal principles applicable to computer information transactions. Secondly, it suggests that if the individual is risk averse, the acceptance set for electronic transactions will be a convex set, and that the application of the Act will make the acceptance set more expanded by lowering the probability of conflicts and by downsizing the risk averness. Thirdly, it also suggest that through the mothod of contingent commodities analysis, the application of the Act by means of its restricted regulations will give more expected utility than the absence of the Act. Fourthly, it derives some implications that the degree of legitimate restriction will be affected by the objective risk inherent to the electronic transactions, and the individual's subjective risk-averseness. Finally, it concludes that harmonization of restriction and protection of individual's rights in electronic transaction process will be a necessary condition for more efficient body of law from the law-economic perspectives.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4662-4679
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• 2015

Currently, the leakage of internal information has emerged as one of the most significant security concerns in enterprise computing environments. Especially, damage due to internal information leakage by insiders is more serious than that by outsiders because insiders have considerable knowledge of the system's identification and password (ID&P/W), the security system, and the main location of sensitive data. Therefore, many security companies are developing internal data leakage prevention techniques such as data leakage protection (DLP), digital right management (DRM), and system access control, etc. However, these techniques cannot effectively block the leakage of internal information by insiders who have a legitimate access authorization. The security system does not easily detect cases which a legitimate insider changes, deletes, and leaks data stored on the server. Therefore, we focused on the insider as the detection target to address this security weakness. In other words, we switched the detection target from objects (internal information) to subjects (insiders). We concentrated on biometrics signals change when an insider conducts abnormal behavior. When insiders attempt to leak internal information, they appear to display abnormal emotional conditions due to tension, agitation, and anxiety, etc. These conditions can be detected by the changes of biometrics signals such as pulse, temperature, and skin conductivity, etc. We carried out experiments in two ways in order to verify the effectiveness of the emotional recognition technology based on biometrics signals. We analyzed the possibility of internal information leakage detection using an emotional recognition technology based on biometrics signals through experiments.

• 인터넷정보학회논문지
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• 제20권5호
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• pp.9-18
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• 2019

APK (Android Application Package)는 리패키징 공격에 취약하므로 APK 파일 내부에 난독화 기술이 적용되어 있다. 하지만 리버스 엔지니어링 기술 역시 더욱 고도화 됨에 따라 또다른 위조 모바일 APK 파일이 개발 및 배포되고 있어 새로운 대응 방식이 필요하다. 블록체인은 암호화 방식을 사용하여 연결 및 보호되는 레코드 블록이 지속적으로 추가되는 방식으로, 각 블록에는 일반적으로 이전 블록의 암호화 해시값, 타임스탬프 및 트랜잭션 데이터 등을 포함하고 있다. 따라서, 일단 블록체인에 기록되면 해당 블록의 데이터는 이후에 생성된 모든 블록을 변경하지 않고서는 소급해서 변경/수정할 수 없다. 그러므로 블록체인 기술을 적용하면 모바일 APK 파일에 대한 정상 및 위조 여부를 확인할 수 있다. 이에 본 논문에서는 Hyperledger Composer를 이용한 컨소시움 블록체인 프레임워크를 기반으로 합법적인 APK를 블록체인 내에 기록하고 유지함으로써 위조 APK에 대한 검출 기능을 제공하는 DApp (분산형 애플리케이션)을 개발하였다. 제안된 DApp을 통해 사용자의 스마트폰에 위조된 앱이 설치 되는 것을 사전에 방지 할 수 있으므로 궁극적으로는 정상적이고 합법적인 안드로이드 모바일 앱 사용 환경을 제공할 것으로 기대된다.

• International Journal of Advanced Culture Technology
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• 제10권4호
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• pp.576-582
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• 2022

In this paper, we discuss the relative positioning of Wh-related English prepositions in a Wh-interrogative construction within the Optimality Theory [1-2]. By employing the two key constraints such as ^*Prep-Str and Align which are developed for the positioning of Wh-related prepositions from Romance languages such as French and Italian [3] and for the positioning of Wh-related prepositions from the middle English prose from 1500 to 1900 [4-6], and by slightly modifying the constraint hierarchy of ^*Prep-STR >>Align into ^**PrepSTR <<>>Align, Choi argues that his new theory can properly explain the unique behaviors of English Whrelated prepositions being able to take two 'optional' operations such as pied-piping and stranding to find legitimate landing sites in a Wh-interrogative construction [7]. However, this new analysis again reveals the following critical problems: (1) Unlike the 'light' English Wh-related prepositions which can two optional operations for legitimate landing sites in a Wh-interrogative construction, 'heavy' Wh-related English prepositions are not allowed to have such two options: they take just one option of pied-piping only. Thus, (2) his argumentation based on the existing constraints and the modified constraint hierarchy is neither general enough nor proper to explain the issue of the relative positioning for all English Wh-related preposition cases. To include such exceptional syntactic property of the 'heavy' preposition cases within the Optimality Theory, we suggest a new constraint of ^*HPrep-STR ranked at the highest position of the constraint hierarchy to disallow a 'heavy' or multi-syllabic Wh-related English preposition to stay alone at the end of a sentence. The new final hierarchy of constraints we suggest to explain the exceptional positioning of 'heavy' Wh-related prepositions together with the other 'light' Wh-related prepositions in English Wh-interrogative construction will be as follows: ^*HPrep-STR>>Align<<>>^*Prep-STR.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.17-20
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• 2005

In this work, we compared several feature selection methods in the field of spam mail filtering. The proposed fuzzy inference method outperforms information gain and chi squared test methods as a feature selection method in terms of error rate. In the case of junk mails, since the mail body has little text information, it provides insufficient hints to distinguish spam mails from legitimate ones. To address this problem, we follow hyperlinks contained in the email body, fetch contents of a remote web page, and extract hints from both original email body and fetched web pages. A two-phase approach is applied to filter spam mails in which definite hint is used first, and then less definite textual information is used. In our experiment, the proposed two-phase method achieved an improvement of recall by 32.4% on the average over the $1^{st}$ phase or the $2^{nd}$ phase only works.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.21-25
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• 2005

In this paper, we constructed a two-phase spam-mail filtering system based on the lexical and conceptual information. There are two kinds of information that can distinguish the spam mail from the legitimate mail. The definite information is the mail sender's information, URL, a certain spam list, and the less definite information is the word list and concept codes extracted from the mail body. We first classified the spam mail by using the definite information, and then used the less definite information. We used the lexical information and concept codes contained in the email body for SVM learning in the $2^{nd}$ phase. According to our results the spam precision was increased if more lexical information was used as features, and the spam recall was increased when the concept codes were included in features as well.