• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.7 no.6
• /
• pp.110-120
• /
• 2008

Cognitive Radio (CR) technology is proposed for using the unused spectrum band efficiently because of the spectrum scarcity problems. Spectrum sensing technology is one of the key challenge issues in cognitive radio technologies, which enables unlicensed users to identify and utilize vacant spectrum resource allocated to primary users. In this paper, the cooperative spectrum sensing technologies apply the ITS(Intelligent Transport System) and performance of signal detection analyzes. Then, we utilize the OR-rule and AND-rule for the cooperative signal detection. These data fusion rules improve the performance and reliability of the signal detection.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.9
• /
• pp.2323-2340
• /
• 2012

Recent advances in cognitive radio technology have drawn immense attention to higher layer protocols above medium access control, such as transmission control protocol (TCP). Most proposals to improve the TCP performance in cognitive radio (CR) networks have assumed that either all nodes are in CR networks or the TCP sender side is in CR links. In those proposals, lower layer information such as the CR link status could be easily exploited to adjust the congestion window and improve throughput. In this paper, we consider a TCP network in which the TCP sender is located remotely over the Internet while the TCP receiver is connected by a CR link. This topology is more realistic than the earlier proposals, but the lower layer information cannot be exploited. Under this assumption, we propose an enhanced TCP protocol for CR networks called TCP for cognitive radio (TCP-CR) to improve the existing TCP by (1) detection of primary user (PU) interference by a remote sender without support from lower layers, (2) delayed congestion control (DCC) based on PU detection when the retransmission timeout (RTO) expires, and (3) exploitation of two separate scales of the congestion window adapted for PU activity. Performance evaluation demonstrated that the proposed TCP-CR achieves up to 255% improvement of the end-to-end throughput. Furthermore, we verified that the proposed TCP does not deteriorate the fairness of existing TCP flows and does not cause congestions.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.20 no.1
• /
• pp.123-128
• /
• 2010

To increase the chance of the success of project, it is necessary to identify the important factors influencing the performance of project. Cognitive map has been used for analysing by investigating causal links among relevant factors. A fuzzy cognitive map (FCM) is an extension of a cognitive map with the additional capability of representing feedback through weighted causal links. Project performance is influenced by several factors such as input resources, possibility of achievement, concern of others and so on. The object of this paper is to develop the project success model of enterprise using a fuzzy cognitive map approach to investigate the degree of causal relationship between project performance and these factors.

• Journal of Korean Physical Therapy Science
• /
• v.19 no.4
• /
• pp.35-40
• /
• 2012

Background : The purpose of this study is to provide the basic data. Elderly cognitive identify the difference between dynamic balance and quality of life according to the performance level of the clinical exercise therapy and cognitive training. Methods : This study was conducted to collect data from October 17th in 2011 until October 28th, to target seniors who living in Yong-in, Gyeonggi-do. Results : The results of the statistical analysis according to the cognitive ability to function. Higher cognitive functions, the dynamic balance ability was higher, and higher quality of life. Also showed that the dynamic balance ability and a high quality of life to the higher cognitive functions(p<.05). Conclusion : For the maintenance and promotion of cognitive function in the elderly, physical therapy approach seems to improve the quality of life and still plays an important role, as well as the promotion of dynamic balance ability. Therefore, to improve cognitive function is thought to be the appropriate intervention methods and approaches to be developed.

• 한국노년학
• /
• v.30 no.1
• /
• pp.81-91
• /
• 2010

The purpose of this study was to test a validity and reliability of Cognitive Performance Scale(CPS), a cognitive measure generated from 5 items(comatose status, decision making, short-term memory, making self understood, and eating). Method: 393 patients in 2 hospitals for the elderly with dementia were measured with CPS by two nurses independently. The inter-rater agreement was tested by comparing two scores. The CPS score was compared with GDS, which was measured by doctors and nurses, and MMSE score which was drawn from the claim data of Health Insurance Review & Assessment Service. Result: The correlation coefficient between CPS and GDS was 0.742(p<0.0001), CPS and MMSE was -0.794(p<0.0001). The Cronbach's coefficient alpha of CPS was 0.742, Kappa value was 0.772~1.000. The CPS showed high validity and reliability in long term care hospitals of Korea.

• Journal of applied mathematics & informatics
• /
• v.29 no.5_6
• /
• pp.1295-1302
• /
• 2011

We present an analytic model of an unslotted opportunistic spectrum access (OSA) network and evaluate its performance such as interruption probability, service completion time, and throughput of secondary users. Numerical examples are given to show the performance of secondary users in cognitive networks. The developed modeling and analysis method can be used to evaluate the performance of various OSA networks.

• The Journal of Korean Physical Therapy
• /
• v.30 no.5
• /
• pp.193-198
• /
• 2018

Purpose: The purpose of this study was to analysis of effectiveness between cognitive function assessment scores and gaming cognitive rehabilitation system in children with intellectual impairment. Methods: Five children (male=5, $age=10.00{\pm}0.80$) with intellectual impairment participated in this study and were randomly assigned to the experiment that played (received) gaming cognitive rehabilitation system (Neuroworld). The children were applied 2 times a week for 30 minutes during 3 months. The children were assessed K-WSIC-VI (Korean-Wechsler intelligence scale for children-fourth edition) and recorded that gained score in gaming cognitive rehabilitation system before and after intervention. K-WSIC-VI contained five primary index scores: verbal comprehension index, visual spatial index, fluid reasoning index, working memory index, and processing speed index. Gaming cognitive rehabilitation system scoring was composed visual recall, target recall, sequence recall, selective attention, continuous attention, and exploration. Results: In the intelligence quotient (IQ) of K-WSIC-VI, there were significant increased in all children. The visual recall item was highest effective in all children. However, sequential recall showed the lowest improvement in all children. The performance speed of selective attention item was decreased, this means that children's skills have improved. Also, their ability to explore has improved significantly. Conclusion: In conclusion, gaming cognitive rehabilitation system was significant effectiveness in cognitive function in some categories for children with intellectual impairment. However, the visual recall and performance speed don't represent of all cognitive function. Therefore, further studies will need to verify by applying more subject and longer duration.

• Journal of Korean Public Health Nursing
• /
• v.11 no.1
• /
• pp.118-127
• /
• 1997

The physical function. congnitive performance and the depression of the elderly persons of over 60 years in Pusan Kyungnam Province are studied. For the survey, prepared is a questionnaire which includes 14 items for the physical function, 8 items for the cognitive performance and 12 items for the depression. totaling 34 items. The interactions of the items of each category are analyzed in terms of daily life performances. The results show that. the elders have the problems in cognitive performance rather than the physical function or depression, and there are great variances depending on the individual's background.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.17 no.30
• /
• pp.43-50
• /
• 1994

Work environment has been changed as the development of new techknowledge such as computer industry. The more new techknowledges, the more changes in our work conditions. But our cognitive limits can't pace up to the change of work environment. As a result, rapid work transfer occurs frequently, which increase work stress, work error and deleterous work performance. For many changes, this paper analyse the effect of work performance when the information used in mental work is changed as a sudden impact during dexterous work conditions. When the information impact is intruded in works, performances are reduced, but the react time does not respond sensitively then cognitive process time. So it is recommended to refer the cognitive time as a index of performance when mental work is included.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.12
• /
• pp.5715-5721
• /
• 2011

This research analyzed the cognitive factors affecting stroke patient's activity of daily living performance and suggests the approaches which can contribute to the effective activity of daily living performance in the rehabilitation treatment of stroke patients. In this study, Seoul Computerized NeuroCognitive Function Test (SCNT) and MBI have been performed for 21 patients under extensive rehabilitation treatments, hospitalized in the rehabilitation clinic of A hospital after being diagnosed as a stroke caused by cerebrovascular disorders. To assess the effectiveness of the cognitive factors which affect the stroke patient's activity of daily living performance, activity of daily living performance values were set as dependent variables and 10 cognitive factors were included in the model to carry out analysis of the multiple regression analysis. The results show that stroke patient's activity of daily living performance have statistically significant correlations with divided attention, motor control and selectivir attention. In addition, cognitive factors explained 69.8% of the stroke patient's activity of daily living performance. Consequently, if divided attention and motor control are considered as a focal point of training in the rehabilitation treatment of stroke patients, we can effectively promote the improvement of the activity of daily living performanceroutine activities.