• 제목/요약/키워드: Differential Services

검색결과 150건 처리시간 0.024초

스트림 암호 Rabbit에 대한 전력분석 공격 (Power Analysis Attacks on the Stream Cipher Rabbit)

  • 배기석;안만기;박제훈;이훈재;문상재
    • 정보보호학회논문지
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    • 제21권3호
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    • pp.27-35
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    • 2011
  • 무선 센서 네트워크(wireless sensor network)의 센서 노드는 특성상 전력 소모량, 전송 속도 및 도달 거리 등이 고려되어 설계되야 하며, 여러 형태의 공격(도청, 해킹, 가입자 비밀정보 유출, 서비스 도착상태 등)에 안전해야 한다. 최근 유럽연합의 eSTREAM 공모사업에서 소프트웨어 분야에 선정된 Rabbit 알고리듬은 ISO/IEC 18033-4 기술분야에 추가 선정되었으며 무선 센서 네트워크에 적용 가능한 스트림 암호이다. 이러한 Rabbit 알고리듬은 이론적 분석에 의해 부채널분석 공격에 대한 복잡도가 중간수준(medium)으로 평가됨에 따라, 본 논문에서는 Rabbit에 대한 전력분석 공격방법을 제안하고 실험을 통하여 검증하였다. 실험을 위해서 프로그래밍이 가능한 고성능 8비트 RISC 계열의 AVR 마이크로프로세서 (ATmega128 L)를 장착한 IEEE 802.15.4/ZigBee 보드에 전력분석 공격의 대응방법이 적용되지 않은 시스템을 구현하고, 해밍무게 모델을 적용한 전력분석 공격을 실시하였다.

온라인 입소문이 병원선택에 미치는 영향의 카노속성에 따른 차이 (Differential effects of online word-of-mouth about attractive and one-dimensional Kano attributes on hospital selection)

  • 김수정;김준용
    • 한국병원경영학회지
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    • 제27권3호
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    • pp.1-14
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    • 2022
  • Purposes: This purpose of this study was to check how much the online word of mouth influences on customer's hospital selection according to Kano's model. Methodology: Kano classified the attributes that affect customer's satisfaction into attractive, one-dimensional, indifferent, must-be, and reverse attributes. Among them, attractive and one-dimensional attributes make up the largest portion in hospital selection. Based on this, the influence of positive or negative online reviews on the selection of hospitals was investigated. Differentiated service was selected as the attractive attributes, and a kind, sufficient explanation was selected as the one-dimensional attributes. Then a questionnaire was conducted how much the positive or negative online reviews influence on hospital selection, respectively. It was conducted from August 7 to September 7, 2021 for medical consumers in their 20s and older who have used medical services for the past 3 years, and the final 142 questionnaires were analyzed. All data was analyzed by chi-square and two-way ANOVA using SPSS ver 25.0. Findings: The results showed that, in one-dimensional attributes, the difference between positive and negative reviews was not statistically significant, but in attractive attributes, positive and negative reviews showed a statistically significant difference. It suggests that positive reviews on attractive attributes had a greater influence on hospital selection. In terms of hospital selection, when the experimental participants were exposed to the positive reviews, the hospital selection ratio did not differ by Kano's attributes, but to the negative reviews it differed. The hospital selection ratio, even after they were exposed to negative reviews, was higher in the attractive attributes than in the one-dimensional attributes. Practical Implication: This study confirmed that hospital selection is influenced differently depending on the Kano's attributes and the direction of the reviews, and suggests that marketers should respond differently to each Kano's attributes when they deal with online reviews of hospitals.

The Effects of Watching a Virtual Reality (VR) Forest Video on Stress Reduction in Adults

  • Hong, Sungjun;Joung, Dawou;Lee, Jeongdo;Kim, Da-Young;Kim, Soojin;Park, Bum-Jin
    • 인간식물환경학회지
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    • 제22권3호
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    • pp.309-319
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    • 2019
  • This study was conducted to investigate the effects of watching a virtual reality (VR) forest video on stress reduction in adults. Experiments were performed in an artificial climate chamber where temperature, humidity and illumination were controlled. To cause stress in subjects, the subjects were asked to multiply two digit numbers by one digit numbers for two minutes. The subjects then watched a VR forest video for five minutes. During the experiment, the heart rate variability (HRV) and heart rate (HR) of subjects were continuously measured for evaluating their physiological state. After measuring the baseline and watching a VR forest video, their psychological state was evaluated using the profile of mood state (POMS), semantic differential (SD) method, and positive affect and negative affect schedule (PANAS). The results of physiological evaluation after watching a VR forest video showed a decrease in the stress index and HR, an increase in the activity of the parasympathetic nervous system, and the standard deviation of normal to normal RR intervals (SDNN). The results of psychological assessment confirmed that watching a VR forest video induced "comfort", "natural", and "soothed" feelings in subjects. In addition, watching a VR forest video decreased "tension-anxiety (T-A)", "depression-dejection (D)", "anger-hostility (A-H)", "fatigue (F)", "total mood disturbance (TMD)", and increased "vigor (V)" compared to the base line, and decreased "negative affect" and increased "positive affect." These results indicate that watching a VR forest video decreases adults' stress index, stabilizes physiological state, and has a positive impact on psychological state. The findings of this study can serve as a basis for providing forest welfare services to people in the blind spots of forest welfare, and can lay a foundation for the adoption of VR, one of the technologies of the fourth industrial revolution in forestry.

Nonlinear intelligent control systems subjected to earthquakes by fuzzy tracking theory

  • Z.Y. Chen;Y.M. Meng;Ruei-Yuan Wang;Timothy Chen
    • Smart Structures and Systems
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    • 제33권4호
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    • pp.291-300
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    • 2024
  • Uncertainty of the model, system delay and drive dynamics can be considered as normal uncertainties, and the main source of uncertainty in the seismic control system is related to the nature of the simulated seismic error. In this case, optimizing the management strategy for one particular seismic record will not yield the best results for another. In this article, we propose a framework for online management of active structural management systems with seismic uncertainty. For this purpose, the concept of reinforcement learning is used for online optimization of active crowd management software. The controller consists of a differential controller, an unplanned gain ratio, the gain of which is enhanced using an online reinforcement learning algorithm. In addition, the proposed controller includes a dynamic status forecaster to solve the delay problem. To evaluate the performance of the proposed controllers, thousands of ground motion data sets were processed and grouped according to their spectrum using fuzzy clustering techniques with spatial hazard estimation. Finally, the controller is implemented in a laboratory scale configuration and its operation is simulated on a vibration table using cluster location and some actual seismic data. The test results show that the proposed controller effectively withstands strong seismic interference with delay. The goals of this paper are towards access to adequate, safe and affordable housing and basic services, promotion of inclusive and sustainable urbanization and participation, implementation of sustainable and disaster-resilient buildings, sustainable human settlement planning and manage. Simulation results is believed to achieved in the near future by the ongoing development of AI and control theory.

Progesterone 농도측정(濃度測定)에 의한 유우(乳牛)의 번식효율증진(繁殖效率增進)에 관한 연구(硏究) V. 혈장(血漿) progesterone 농도측정(濃度測定)에 의한 무발정(無發情)의 감별진단(鑑別診斷) 및 PGF2α 또는 GnRH 치료효과(治療效果)의 판정(判定) (Progesterone assays as an aid for improving reproductive efficiency in dairy cattle V. Plasma progesterone determination as applied to the differential diagnosis of reproductive disorders and judgement of treatment responses to PGF2α or GnRH treatment)

  • 강병규;최한선;손창호;오기석;강현구;김삼주;김혁진;김남기
    • 대한수의학회지
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    • 제35권3호
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    • pp.603-613
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    • 1995
  • Plasma progesterone($P_4$) assay has been introduced to apply to the differential diagnosis of reproductive disorders and the monitoring of responses of ovarian dysfunction to $PGF_2{\alpha}$ or GnRH treatment in the 204 postpartum and postinsemination subestrus dairy cows. 1. The incidence rate of reproductive disorders in 204 subestrus cows, diagnosed by palpation per rectum and plasma $P_4$ determination using 'Two sample test'(Day 0+Day 10) were as follows; silent heat or error of estrus detection 110(53.9%), persistent corpus luteum 26(12.7%), follicular cyst 16(7.8%), inactive ovary 12(5.9%), luteal cyst 11(5.4%), granulosa cell tumor of ovary 1(0.5%), fetal mummification 1(0.5%), endometritis 15(7.4%) and pyometra 12(5.9%), respectively. 2. After the $PGF_2{\alpha}$ treatment to the 76 cows with silent heat or error of estrus detection, persistent corpus luteum, or luteal cyst, plasma $P_4$ concentrations at day 3 post treatment using 'Two sample test'(Day 0+Day 3) remained low(<1.0ng/ml) in all 76 cows. Therefore all 76 cows responded positively to $PGF_2{\alpha}$ treatment. Seventeen cows with follicular cyst or inactive ovary were treated with GnRH. All 7 cows with follicular cyst and 4 cows with inactive ovary remained high($${\geq_-}1.0ng/ml$$) a plasma $P_4$ concentrations at day 12 post treatment using 'Two sample test'(Day 0+Day 12), but 6 cows with inactive ovary remained low(<1.0ng/ml) a plasma $P_4$ concentrations. Therefore all 7 cows with follicular cyst and 4 cows with inactive ovary responded positively, but 6 cows with inactive ovary responded negatively to GnRH treatment. 3. The mean days from treatment to first service, number of cows conceived on first service(%), mean number of services per conception, mean days from initial treatment to conception, and mean number of cows conceived by 100 days post treatment(%) were 5.0 and 26.2 days, 45(59.2%) and 6(35.3%) cows, 1.5 and 1.7 services, 13.6 and 22.6 days, and 62(81.6%) and 9(52.9%) cows in group of $PGF_2{\alpha}$ and GnRH treatment, respectively. These results indicated that plasma $P_4$ assay was practical as an aid to diagnosing reproductive disorders and to monitoring responses of ovarian dysfunction to $PGF_2{\alpha}$ and GnRH treatment in subestrus cows.

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무리행동과 지각된 유용성이 이러닝 컨텐츠 구매의도에 미치는 영향: 구매경험에 의한 비교분석 (The Effect of Herding Behavior and Perceived Usefulness on Intention to Purchase e-Learning Content: Comparison Analysis by Purchase Experience)

  • 유철우;김용진;문정훈;최영찬
    • Asia pacific journal of information systems
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    • 제18권4호
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    • pp.105-130
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    • 2008
  • Consumers of e-learning market differ from those of other markets in that they are replaced in a specific time scale. For example, e-learning contents aimed at highschool senior students cannot be consumed by a specific consumer over the designated period of time. Hence e-learning service providers need to attract new groups of students every year. Due to lack of information on products designed for continuously emerging consumers, the consumers face difficulties in making rational decisions in a short time period. Increased uncertainty of product purchase leads customers to herding behaviors to obtain information of the product from others and imitate them. Taking into consideration of these features of e-learning market, this study will focus on the online herding behavior in purchasing e-learning contents. There is no definite concept for e-learning. However, it is being discussed in a wide range of perspectives from educational engineering to management to e-business etc. Based upon the existing studies, we identify two main view-points regarding e-learning. The first defines e-learning as a concept that includes existing terminologies, such as CBT (Computer Based Training), WBT (Web Based Training), and IBT (Internet Based Training). In this view, e-learning utilizes IT in order to support professors and a part of or entire education systems. In the second perspective, e-learning is defined as the usage of Internet technology to deliver diverse intelligence and achievement enhancing solutions. In other words, only the educations that are done through the Internet and network can be classified as e-learning. We take the second definition of e-learning for our working definition. The main goal of this study is to investigate what factors affect consumer intention to purchase e-learning contents and to identify the differential impact of the factors between consumers with purchase experience and those without the experience. To accomplish the goal of this study, it focuses on herding behavior and perceived usefulness as antecedents to behavioral intention. The proposed research model in the study extends the Technology Acceptance Model by adding herding behavior and usability to take into account the unique characteristics of e-learning content market and e-learning systems use, respectively. The current study also includes consumer experience with e-learning content purchase because the previous experience is believed to affect purchasing intention when consumers buy experience goods or services. Previous studies on e-learning did not consider the characteristics of e-learning contents market and the differential impact of consumer experience on the relationship between the antecedents and behavioral intention, which is the target of this study. This study employs a survey method to empirically test the proposed research model. A survey questionnaire was developed and distributed to 629 informants. 528 responses were collected, which consist of potential customer group (n = 133) and experienced customer group (n = 395). The data were analyzed using PLS method, a structural equation modeling method. Overall, both herding behavior and perceived usefulness influence consumer intention to purchase e-learning contents. In detail, in the case of potential customer group, herding behavior has stronger effect on purchase intention than does perceived usefulness. However, in the case of shopping-experienced customer group, perceived usefulness has stronger effect than does herding behavior. In sum, the results of the analysis show that with regard to purchasing experience, perceived usefulness and herding behavior had differential effects upon the purchase of e-learning contents. As a follow-up analysis, the interaction effects of the number of purchase transaction and herding behavior/perceived usefulness on purchase intention were investigated. The results show that there are no interaction effects. This study contributes to the literature in a couple of ways. From a theoretical perspective, this study examined and showed evidence that the characteristics of e-learning market such as continuous renewal of consumers and thus high uncertainty and individual experiences are important factors to be considered when the purchase intention of e-learning content is studied. This study can be used as a basis for future studies on e-learning success. From a practical perspective, this study provides several important implications on what types of marketing strategies e-learning companies need to build. The bottom lines of these strategies include target group attraction, word-of-mouth management, enhancement of web site usability quality, etc. The limitations of this study are also discussed for future studies.

창업보육서비스에 따른 입주기업의 창업보육센터 의존도에 관한 연구 (A Study on Startups' Dependence on Business Incubation Centers)

  • 박재성;리철;김재전
    • 중소기업연구
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    • 제31권2호
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    • pp.103-120
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    • 2009
  • 창업보육센터는 창업을 준비하는 예비창업자 및 신규 창업자에게 사업을 영위하는데 필요한 자원 및 서비스를 제공하고, 사업을 수행하는 과정에서 발생되는 다양한 문제의 해결에 도움을 주고 있다. 그러나 이러한 지원은 상황에 따라 기업의 자생력을 높이기보다는 창업보육센터에 대한 의존도를 높이는 경향이 있다. 본 연구는 창업보육서비스를 제공형태에 따라 인프라 지원, 네트워크 연계 지원, 직접 지원으로 분류한 후에 이들 서비스의 제공이 입주기업의 창업보육센터 의존도에 미치는 영향관계를 살펴보고, 아울러 입주기간에 따른 조절효과를 살펴보았다. 연구결과 세 가지 보육서비스 모두 의존도에 영향을 미치는 것으로 파악되었으며, 입주기간에 따른 조절효과는 기간이 늘어날수록 네트워크 연계 지원서비스에 정의 효과가 있는 반면 직접 지원서비스는 부의 효과가 있는 것으로 파악되었다. 이러한 결과는 입주기간이 늘어감에 따라 직접 지원서비스의 경우에는 입주기업이 센터의 자원을 흡수하여 기업의 역량으로 만들어 가지만, 네트워크 연계 지원서비스는 기업의 센터에 대한 의존도를 높이고 있다는 것을 보여준다. 따라서 신생기업이 자생력을 갖기 위해서는 보육서비스를 보육기간에 따라 차별적으로 제공해야 한다는 시사점을 제시하고 있다.

스마트 폰 기반 Self-Tour 서비스 기술 연구 (Self-Tour Service Technology based on a Smartphone)

  • 배경율
    • 지능정보연구
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    • 제16권4호
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    • pp.147-157
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    • 2010
  • 아이폰의 등장과 함께 스마트 폰에 대한 관심이 높아지고, 통신사업자를 통해야만 가능했던 다양한 서비스가 스마트 폰을 통해서 직접 제공할 수 있는 환경이 가능해졌다. 전세계적으로 해외 관광객이 증가하면서 관광가이드 없이 자신의 노력으로 여행을 다니는 개인관광객도 증가하고 있다. 그러나 우리나라를 방문하는 외국인들이 개인적으로 여행을 즐기기에는 언어소통이나 제공되는 정보의 부족으로 어려움을 느끼고 있다. 본 연구에서는 스마트 폰이 탑재하고 있는 GPS와 WiFi 또는 3G 무선망을 통해서 사전에 설정된 관광 정보 카테고리에 따라서 관광객의 위치에 따른 관련 정보를 자동으로 제공함으로써 관광객의 편의성을 높이는 서비스 기술을 개발하였다. 개발된 서비스는 인사동을 대상으로 시험하였으며, 사용자의 선택과 같은 불편함 없이 주변정보를 제공함으로써 관광에 대한 편의성을 최대한 높였다.

동일질환에 대한 보험의료 이용경로 분석 : 직장 의료보험조합 적용인구를 대상으로 (An Analysis on the Utilization Patterns of Health Care Facilities for an Employees Health Insurance Program)

  • 문옥륜;김창엽
    • 보건행정학회지
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    • 제1권1호
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    • pp.116-135
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    • 1991
  • Few studies have been conducted on the detailed routes of medical care utilization under the National Health Insurance. This study was undertaken to identify the utilization patte군 of health care facilities among industrial workers and their dependents. One of the largest health insurance association was purposively chosen for this objective. The association had 345, 757 members as of 31 December, 1990. The study sample of 297, 948 subjects have been drawn from the membership pool on the basis of their continuous membership status during 1 January through 31 December 1990. This study has tried to identify differential utilization patterns between acute and chronic conditions, and among standard income classes. All the diagnoses were recoded in a manner to achieve the objective of this study. As for acute diseases, most age group had used one medical facility as much as by 60% except the age group of 1-4, This young age group had used over three different health facilities as much as by 10.9-15.8%. The finding suggests that some policy measures by sought for remedying the excessive/inappropriate use of services. In addition, mid-income classes(between 17 and 48) were more likely to use multiple sources of care than lower income classes(between 1 and 16) and upper income classes(above 49). This study has revealed that chronic cases are more likely to pursue multiple sources of care, however those with chronic conditions tend to use single health facility more than those with acute conditions(67.9% versus 52.4%). As many as 12.2% have visited more than three health facilities in chronic conditions, but 5.9% for acute conditions. The most likely source of care was primary clinics for both acute and chronic conditions. Compared with the role of general hospital, small-size hospitals found to play a minimal role in the care and referral of patients. This indicates the need of strengthening the function of small-size hospitals. While a minor cross utilization of western medicine and pharmacy was noted, no significant boundary crossing was identified between western medicine and oriental medicine, or between pharmacy and oriental medicine. It is too early to confirm that whether there is substitutability or cross utilization among these alternative sources of care. A further study is needed to identify these relationship.

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시각비교를 위한 eLoran 수신기 지연측정 기술 (A Time Comparison Measurement Technique for eLoran Receivers)

  • 이창복;이종구;이영규;황상욱;양성훈
    • 한국항해항만학회지
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    • 제40권6호
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    • pp.385-390
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    • 2016
  • eLoran은 측위, 항법, 시각 분야에서 요구 정확도에 따라 GPS의 대체 또는 백업시스템으로 사용될 수 있다. eLoran 송신국들은 UTC에 동기 되어 있으므로 TOA를 근거로 한 all-in-view 수신이 가능하여 높은 정확도의 시각 동기와 항법이 가능하다. 또한 LDC를 통해 송신국 및 dLoran 보정 정보 등을 방송함으로써 향상된 PNT를 제공한다. 본 논문에서는 eLoran을 이용한 정밀 시각비교 측정에 필수적인 eLoran 타이밍 수신기의 지연 시간에 관련된 것들을 측정하여 보정값으로 반영하는 기술을 제시하였다. 송신기 종단의 전류 결합기로부터 로란 신호를 추출하여 3 번째 사이클과 교차하는 지점에서 펄스를 생성하는 장치를 구성하고 그 펄스를 기준으로 지연 시간을 측정하는 장치를 구현하였다. 수신기 지연은 상용 eLoran 수신기와 능동형 자기장, 전기장 안테나와 수동형 루프 안테나를 사용하여 각각의 안테나를 연결하였을 때의 지연시간을 측정하였다. 이와 같은 방법으로 교정된 eLoran 타이밍 수신기를 공통시계 비교법에 이용하면 GNSS 이용 시각비교의 백업 시스템으로서 정밀한 시각비교가 필요한 분야에 활용할 수 있다.