• Spatial Information Research
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• 제14권4호
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• pp.433-449
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• 2006

본 연구는 인간이 인지거리를 지도화 함에 있어, 성별, 연령, 학년, 수학기간 등의 개인적인 요인과 거리 추정에 사용된 기준점의 상대적인 위치가 거리 추정에 어떤 영향을 주는 지를 위치정보 시스템을 이용한 현장 실험을 통해 파악하고자 하였다. 연구 방법으로는, 미국 캔자스대학교에 재학 중인 학부생과 대학원생을 대상으로 캠퍼스 방문을 통한 설문조사를 실시하였다. 자료분석 결과, 여학생 그룹의 거리추정 정확도가 인종이나 학년에 관계없이 남학생 그룹에 비해 높았으며, 전체적으로 학년과 연령이 높아지고 수학기간이 길어짐에 따라 거리 추정 정확도의 분산정도가 감소하는 것으로 나타났다. 인지거리 지도화를 위해 제시된 2개 기준점에 가까이 위치한 건물 일수록 거리 추정의 정확도가 높았으며, 설문조사 지점이 기준점에 가까울수록 거리 추정의 오차가 감소하였다. 상관관계 분석 결과, 남학생 그룹의 거리추정 오차값이 여학생 그룹에 비해 건물-기준점 간 거리, 그리고 피실험자-기준점 간 거리와 더 강한 상관관계를 가진 것으로 보아, 남학생이 여학생에 비해 기준점에 근거한 공간적 축척을 더 면밀하게 이용하는 것으로 판단된다.

• 대한통합의학회지
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• 제8권2호
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• pp.89-95
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• 2020

Purpose : This study aims to evaluate the correlation of cognitive function, activities of daily living (ADL), and driving performance in stroke hemiplegic patients residing in Korea. Methods : Subjects of the study were 18 stroke hemiplegic patients admitted to hospitals situated in Seoul. A clock drawing test (CDT), a modified Barthel index (MBI), and a virtual reality driving simulator (Eca faros-driving simulator) were used to examine their cognitive function, their ADL ability, and their driving skills, respectively. Results : Driving skills of stroke hemiplegic patients were shown to be associated with the CDT evaluation tool (r=-.777) (p<.001), but they were found to have any correlation with MBI (r=-.022) (p>.05). Additionally, an individual's CDT showed that the driving simulator evaluation result (pass/fail) could be discriminated with a sensitivity of 100.0 %, a specificity of 40.0 %, and an accuracy of 66.7 %. The result confirmed that the CDT is a useful evaluation tool for screening driving ability in people with stroke. But the MBI did not show any significant results (sensitivity of 62.5 %, specificity of 40.0 %, and predicted the results of the simulator with 50.0 % of accuracy) (p>.05). Conclusion : This study shows that cognitive function influences the driving performance in people with stroke. Driving skills of stroke hemiplegic patients are seen to be highly related to CDT. In the field of driving rehabilitation, these findings could be useful for evaluating driving skills relating to CDT. Furthermore, the study results will set a guideline for domestic occupational therapists to use the evaluation tool for assessing driving abilities in people with stroke.

• 인지과학
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• 제30권4호
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• pp.175-197
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• 2019

고차적 사고를 요구하는 글쓰기는 배운 지식을 활용하고 발전시키게 한다. 학습 장면에서 글쓰기를 더 많이 활용하기 위해서는 동료평가를 도입하는 동시에 동료평가의 정확도를 높일 필요가 있다. 본 연구에서는 동료평가의 정확도를 높이는 방안으로, 평가 기준에 대해 학생들끼리 토론하게 하거나 전문가의 평가를 참고하도록 하는 두 방안을 탐색하였다. 대학생 150명을 대상으로 한 실험 결과, 동료평가 후 전문가의 평가를 참고했던 집단이 평가했던 글을 다시 평가할 때는 평가 정확도가 향상되었지만, 새로운 글을 평가할 때는 향상되지 않았다. 반면에, 동료평가 후 평가 기준에 대하여 토론을 진행했던 집단은 평가했던 글을 다시 평가할 때는 평가 정확도가 향상되지 않았지만, 새로운 글을 평가할 때는 향상됨을 발견하였다. 또한 토론 집단의 경우 평가 기준에 대한 토론에서 총 발언 수가 많아질수록 평가 정확도가 높아졌다. 이상의 결과는 평가 기준에 대한 토론에서 적극적이고 자발적인 논의가 활발할수록 이후 동료평가의 정확도가 향상됨을 시사한다.

• 제어로봇시스템학회논문지
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• 제22권2호
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• pp.104-109
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• 2016

In this paper, a localization method for multiple robots based on Bayesian inference is proposed when multiple robots adopting multi-RAT (Radio Access Technology) communications exist in cognitive radio networks. Multiple robots are separately defined by primary and secondary users as in conventional mobile communications system. In addition, the heterogeneous spectrum environment is considered in this paper. To improve the performance of localization for multiple robots, a realistic multiple primary user distribution is explained by using the probabilistic graphical model, and then we introduce the Gibbs sampler strategy based on Bayesian inference. In addition, the secondary user selection minimizing the value of GDOP (Geometric Dilution of Precision) is also proposed in order to overcome the limitations of localization accuracy with Gibbs sampling. Via the simulation results, we can show that the proposed localization method based on GDOP enhances the accuracy of localization for multiple robots. Furthermore, it can also be verified from the simulation results that localization performance is significantly improved with increasing number of observation samples when the GDOP is considered.

• 말소리와 음성과학
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• 제5권1호
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• pp.27-38
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• 2013

Healthcare providers in Korea are using conservative pharmacological treatment for Alzheimer's disease (AD) to delay the progress of the disease or to mitigate its behavioral and neurological symptoms. However, there is a growing need for interventions using practical non-pharmacologic treatment, as the effects of pharmacological treatments has faced limitations. This research provided a cognitive rehabilitation program to 3 AD patients and used a multiple baseline design across subjects to examine the effects. Performing reality orientation therapy (ROT) for 1 cycle (4 weeks) resulted in a slight increase in accuracy and responsiveness on an orientation task, mainly with patients with mild cases of AD. Also, in the sub-domain of the Korean-Mini Mental Status Examination performed to examine changes in cognitive ability, there were minimal changes in place orientation. In functional communication, however, there were no significant differences before and after the intervention. In conclusion, we found that ROT was an effective intervention for improving accuracy and responsiveness in the orientation of patients with mild cases of AD. In future studies, the effect of non-pharmacological interventions can be evaluated more reliably by examining the interaction effects of sample size, length of the intervention, outcome measurements, and pharmacological intervention.

• ETRI Journal
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• 제37권3호
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• pp.491-501
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• 2015

Spectrum sensing is an elementary function in cognitive radio designed to monitor the existence of a primary user (PU). To achieve a high rate of detection, most techniques rely on knowledge of prior spectrum patterns, with a trade-off between high computational complexity and long sensing time. On the other hand, blind techniques ignore pattern matching processes to reduce processing time, but their accuracy degrades greatly at low signal-to-noise ratios. To achieve both a high rate of detection and short sensing time, we propose fast spectrum sensing with coordinate system (FSC) - a novel technique that decomposes a spectrum with high complexity into a new coordinate system of salient features and that uses these features in its PU detection process. Not only is the space of a buffer that is used to store information about a PU reduced, but also the sensing process is fast. The performance of FSC is evaluated according to its accuracy and sensing time against six other well-known conventional techniques through a wireless microphone signal based on the IEEE 802.22 standard. FSC gives the best performance overall.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.58-73
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• 2014

As is well known, cooperative sensing can significantly improve the sensing accuracy as compared to local sensing in cognitive radio networks (CRNs). However, a large number of cooperative secondary users (SUs) reporting their local detection results to the fusion center (FC) would cause much overhead, such as sensing delay and energy consumption. In this paper, we propose a fast cooperative sensing scheme, called double threshold fusion (DTF), to reduce the sensing overhead while satisfying a given sensing accuracy requirement. In DTF, FC respectively compares the number of successfully received local decisions and that of failed receptions with two different thresholds to make a final decision in each reporting sub-slot during a sensing process, where cooperative SUs sequentially report their local decisions in a selective fashion to reduce the reporting overhead. By jointly considering sequential detection and selective reporting techniques in DTF, the overhead of cooperative sensing can be significantly reduced. Besides, we study the performance optimization problems with different objectives for DTF and develop three optimum fusion rules accordingly. Simulation results reveal that DTF shows evident performance gains over an existing scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권12호
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• pp.3266-3285
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• 2023

With the popularity of online learning, intelligent tutoring systems are starting to become mainstream for assisting online question practice. Surrounded by abundant learning resources, some students struggle to select the proper questions. Personalized question recommendation is crucial for supporting students in choosing the proper questions to improve their learning performance. However, traditional question recommendation methods (i.e., collaborative filtering (CF) and cognitive diagnosis model (CDM)) cannot meet students' needs well. The CDM-based question recommendation ignores students' requirements and similarities, resulting in inaccuracies in the recommendation. Even CF examines student similarities, it disregards their knowledge proficiency and struggles when generating questions of appropriate difficulty. To solve these issues, we first design an enhanced cognitive diagnosis process that integrates students' affection into traditional CDM by employing the non-compensatory bidimensional item response model (NCB-IRM) to enhance the representation of individual personality. Subsequently, we propose an affection-enhanced personalized question recommendation (AE-PQR) method for online learning. It introduces NCB-IRM to CF, considering both individual and common characteristics of students' responses to maintain rationality and accuracy for personalized question recommendation. Experimental results show that our proposed method improves the accuracy of diagnosed student cognition and the appropriateness of recommended questions.

• 한국비블리아학회지
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• 제30권4호
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• pp.157-173
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• 2019

인지적 권위는 주어진 정보가 적절하다고 인식하도록 개인의 생각에 영향을 미치기 때문에, 사람들은 자신의 인지적 권위를 기반으로 정보를 평가한다. 본 연구에서는 대학생들이 학업 과제를 수행하기 위해 이용하는 온라인 정보원의 인지적 권위에 대한 인식을 알아보고, 그러한 인식이 웹 페이지, 전자저널, 위키피디아와 같은 정보원의 품질 평가에 영향을 미치는지 알아보고자 한다. 구체적으로, 각 정보원의 저자의 특성, 표면적 특성, 그리고 내용의 특성으로 인한 인지적 권위가 정보의 정확성, 유용성, 완전성, 그리고 전문성을 평가하는 데 미치는 영향을 측정하였다. 이를 위해 대학생들을 대상으로 온라인 설문조사를 실시하였으며, 172개의 유효한 응답을 얻었다. 연구 결과, 정보원의 인지적 권위를 구성하는 모든 특성들이 정보의 정확성, 유용성, 완전성, 그리고 전문성 평가에 유의한 영향을 미치는 것으로 나타났다. 본 연구는 인지적 권위와 정보의 신뢰성의 관계를 온라인 정보원의 맥락에서 확인한 점에서 학문적 의의가 있으며, 정보원에서 제공하는 정보의 품질에 대한 이용자의 신뢰를 얻기 위해서는 시스템 개발자나 정보원 운영자들이 인지적 권위를 형성하는 다양한 요인들을 고려해야 한다는 실질적 함의를 제시한다.

• 대한인간공학회지
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• 제18권2호
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• pp.35-45
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• 1999

Driver centered vehicle design is the important factor for driver's safety, product quality, and so on. Therefore, people has recently recognized the importance of driver centered vehicle design. Especially, in the focus of driver-vehicle interaction system, it is very important factor to ergonomic design of vehicle cockpit. In this study, Sketch Map method was used to measure of driver's cognitive map on IP(Instrument Panel) that is the basic factor to ergonomic design for vehicle cockpit. The compatibility of Sketch Map method was validated for the measurement of driver's cognitive map and then the accuracy between two groups was analyzed using Sketch Map method. Subjects were divided in two groups, the first group of subjects has their own vehicles and driver license, and the second group of subjects doesn't have own vehicle but has driver license. The result showed that for the case of the first group, the shape of IP in the cognitive map was influenced by IP of their each vehicle. However, for the case of the second group, it showed the difference between IP in the cognitive map and IP of experienced vehicle many times because they have been driving various type of vehicle. So, the shape of IP in the cognitive map was influenced by various type of IP.