• Journal of Information Processing Systems
• /
• 제14권2호
• /
• pp.523-538
• /
• 2018

Keystroke dynamics user authentication is a behavior-based authentication method which analyzes patterns in how a user enters passwords and PINs to authenticate the user. Even if a password or PIN is revealed to another user, it analyzes the input pattern to authenticate the user; hence, it can compensate for the drawbacks of knowledge-based (what you know) authentication. However, users' input patterns are not always fixed, and each user's touch method is different. Therefore, there are limitations to extracting the same features for all users to create a user's pattern and perform authentication. In this study, we perform experiments to examine the changes in user authentication performance when using feature vectors customized for each user versus using all features. User customized features show a mean improvement of over 6% in error equal rate, as compared to when all features are used.

• 한국항공운항학회지
• /
• 제26권4호
• /
• pp.1-12
• /
• 2018

Baggage Handling System(BHS) is an important element of ground operation services and the importance is further emphasized as air demand increases and passengers change. If there is a problem with departure baggage handling, the aircraft's gate occupancy time will be longer than the initial plan, resulting in congestion of the anchorage leading to final passenger terminal and mooring and road congestion and arrival or It is delayed until the processing of the baggage of the connecting flight and it can cause an economic loss such as confusion in the operation of the airport. The purpose of this study is to investigate the effect of the perception of service quality of BHS users on public Institutions performance through user satisfaction, user performance, and user loyalty. Analysis results using Structural Equation Model was suggested and its implication was discussed in the conclusion.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.931-934
• /
• 2005

This paper describes an adaptive recommendation system that provides real-time personalized trading advice to the investors based on their profiles and trading information environment. A proposed system integrates Stochastic technical analysis and artificial neural network that incorporates an adaptive user modeling. The user model is constructed and updated based on initial user profile and recorded user interactions with the system. The information presented to each individual user is also tailor-made to fit the user's behavior and preference. A system prototype was implemented in JAVA. Experiments used to evaluate the system's performance were done on both human subjects and synthetic users. The results show our proposed system is able to rapidly learn to provide appropriate advice to different types of users.

• Journal of Communications and Networks
• /
• 제9권2호
• /
• pp.112-117
• /
• 2007

In this paper, we focus on the total transmission power minimization problem for downlink beamforming multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems while ensuring each user's QoS requirement. Although the linear integer programming (LIP) solution we formulate provides the performance upper bound of the margin adaptive (MA) optimization problem, it is hard to be implemented in practice due to its high computational complexity. By regarding each user's equivalent channel gain as approximate independent values and using iterative descent method, we present a heuristic MA resource allocation algorithm. Simulation results show that the proposed algorithm efficiently converges to the local optimum, which is very close to the performance of the optimal LIP solution. Compared with existing space division multiple access (SDMA) OFDM systems with or without adaptive resource allocation, the proposed algorithm achieves significant performance improvement by exploiting the frequency diversity and multi-user diversity in downlink multiple-input single-output (MISO) OFDM systems.

• Journal of information and communication convergence engineering
• /
• 제9권6호
• /
• pp.641-646
• /
• 2011

In this paper, we investigate a power control problem which is very critical in underlay-based spectrum sharing systems. Although an underlay-based spectrum sharing system is more efficient compared to an overlay-based spectrum sharing system in terms of spectral utilization, some practical problems obstruct its commercialization. One of them is a real-time-based power adaptation of secondary transmitters. In the underlay-based spectrum sharing system, it is essential to adapt secondary user's transmit power to interference channel states to secure primary users' communication. Thus, we propose a practical power control scheme for secondary transmitters. The feedback overhead of our proposed scheme is insignificant because it requires one-bit signaling, while the optimal power control scheme requires the perfect information of channel states. In addition, the proposed scheme is robust to feedback delay. We compare the performance of the optimal and proposed schemes in terms of primary user's outage probability and secondary user's throughput. Our simulation results show that the proposed scheme is almost optimal in terms of both primary user's outage probability and secondary user's throughput when the secondary user's transmit power is low. As the secondary user's transmit power increases, the primary user's outage probability of the proposed scheme is degraded compared with the optimal scheme while the secondary user's throughput still approaches that of the optimal scheme. If the feedback delay is considered, however, the proposed scheme approaches the optimal scheme in terms of both the primary user's outage probability and secondary user's throughput regardless of the secondary user's transmit power.

• 한국콘텐츠학회논문지
• /
• 제12권10호
• /
• pp.418-429
• /
• 2012

본 연구는 평가와 보상요인이 지식관리 시스템 도입요인(조직특성, 지식정보특성, 이용자특성)과 성과요인 간에 조절적 역할을 하고 있는지를 실증적으로 분석하였다. 분석 결과 조직 유연성, 신뢰, 지식의 적합성, 기능의 제공정도, 인지된 이익 요인은 KMS 활용도에 조절적인 역할을 하고 있는 것으로 분석되었으며, 사용 용이성, 이용자 전문성 요인은 KMS 활용도에 조절적인 역할을 하지 않는 것으로 나타났다. KMS 만족도에는 조직 유연성, 신뢰, 기능의 제공 정도, 이용자 전문성 요인은 KMS 만족도에 조절적인 역할을 하고 있는 것으로 분석되었으며, 지식의 적합성, 사용 용이성, 인지된 이익 요인은 KMS 만족도에 조절적인 역할을 하지 않는 것으로 나타났다.

• 한국통신학회논문지
• /
• 제31권6A호
• /
• pp.575-585
• /
• 2006

Orthogonal Frequency Division Multiple Access(OFDMA) 시스템에서 사용자는 초기 레인징 과정을 통해서 상향링크의 시간 동기를 획득한다. 기지국 수신기는 특정 사용자의 심볼에 시간 동기화하고 나머지 사용자들의 심볼들은 동기화된 시간과의 오차만큼 Symbol Timing Offset(STO)이 존재한다. 각 사용자의 STO에 의해서 한 OFDMA 심볼 내에 선형적인 위상 성분이 발생하고, 이 위상 성분들이 합성되어 다중 접속 간섭(Multiple Access Interference : MAI)으로 작용한다. 이런 MAI는 기지국 수신기의 레인징 부호 검출 성능을 열화 시키는 원인이 된다. 본 논문에서는 각 사용자의 STO에 의해 발생하는 위상 성분의 추정 및 보상을 위한 공통 레인징 부호를 사용하는 초기 레인징 심볼 구조를 제안한다. 공통 레인징 부호를 사용해서 각 사용자의 STO에 의해 발생한 위상 성분의 평균을 추정하고 보상한다. 이 방식은 MAI의 영향을 억제하여 기존 방식보다 더 향상된 레인징 부호 검출 성능을 제공한다.

• International Journal of Advanced Culture Technology
• /
• 제9권3호
• /
• pp.283-290
• /
• 2021

Recently, correlated superposition coding (CSC) has been proposed to implement non-orthogonal multiple access (NOMA) without successive interference cancellation (SIC), without loss of spectral efficiency, in contrast to conventional independent superposition coding (ISC). However, correlation between signals has reduced the average total allocated power, which results in degraded performance. Thus, in order to avoid the reduction of the average total allocated power owing to correlation between signals, this paper proposes a cross-correlated quadrature amplitude modulation (QAM) NOMA scheme under Rayleigh fading channel surroundings. First, we design the cross-correlated QAM NOMA scheme. Then, simulations demonstrate that for the weaker channel gain's user, the symbol error rate (SER) performance of the proposed cross-correlated QAM NOMA improves largely, whereas for the stronger channel gain's user, the SER performance of the proposed cross-correlated QAM CSM NOMA degrades little, compared to that of the conventional QAM NOMA.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2016년도 춘계학술발표대회
• /
• pp.215-217
• /
• 2016

With the popularity of smart device, mobile applications are playing more and more important role in people's daily life, these applications stores various information which greatly facilitate the user's daily life. However due to the frequent transmission of data in the network also increases the risk of data leakage, more and more developers began to focus on how to protect user data. Current mainstream development models include Native development, Web development and Hybrid development. Hybrid development is based on JavaScript and HTML5, it has a cross platform advantages similar to Web Apps and a good user experience similar to Native Apps. In this paper according to the features of Hybrid applications, we proposed a security scheme in Hybrid development model implements message-level data encryption to protect user information. And through the performance evaluation we found that in some scenario the proposed security scheme has a better performance.

• 한국콘텐츠학회논문지
• /
• 제11권4호
• /
• pp.312-320
• /
• 2011

이 논문에서는 일개 POC(Point Of Care) 시스템을 사용하는 의료기관을 중심으로 의약품 처방조제지원 시스템(Clinical Decision Support System, CDSS)과 조직성과와의 관계를 규명하는 것에 목적을 두고 있다. 이를 위하여 정보시스템 평가요소에 대해 정의를 내리고, CDSS의 성과 평가 모형을 제시하여 설문조사 분석을 통해 의약품 처방조제지원시스템의 도입 효과를 밝히고자 하였다. 분석결과 시스템 품질을 제외하고는 각 평가 영역들 사이에 인과성이 존재하는 것으로 분석되었으며, 통계적으로 유의하게 지지되는 것으로 분석되었다. 평가모형 검증결과 의약품처방최적화를 위한 CDSS의 시스템 품질이 사용자 만족도에 영향을 미친다는 근거를 발견할 수 없었다. 그러나 정보품질이 사용자의 만족도에 긍정적인 영향을 미치며 사용자 만족은 조직성과에 긍정적인 영향을 미치는 것으로 나타났다.