• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.7-15
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• 2020

Purpose: In modern radiotherapy technology, several methods of image guided radiation therapy (IGRT) are used to deliver accurate doses to tumor target locations and normal organs, including CBCT (Cone Beam Computed Tomography) and other devices, ExacTrac System, other than CBCT equipped with linear accelerators. In previous studies comparing the two systems, positional errors were analysed rearwards using Offline-view or evaluated only with a Yaw rotation with the X, Y, and Z axes. In this study, when using CBCT and ExacTrac to perform 6 Degree of the Freedom(DoF) Online IGRT in a treatment center with two equipment, the difference between the set-up calibration values seen in each system, the time taken for patient set-up, and the radiation usefulness of the imaging device is evaluated. Materials and Methods: In order to evaluate the difference between mobile calibrations and exposure radiation dose, the glass dosimetry and Rando Phantom were used for 11 cancer patients with head circumference from March to October 2017 in order to assess the difference between mobile calibrations and the time taken from Set-up to shortly before IGRT. CBCT and ExacTrac System were used for IGRT of all patients. An average of 10 CBCT and ExacTrac images were obtained per patient during the total treatment period, and the difference in 6D Online Automation values between the two systems was calculated within the ROI setting. In this case, the area of interest designation in the image obtained from CBCT was fixed to the same anatomical structure as the image obtained through ExacTrac. The difference in positional values for the six axes (SI, AP, LR; Rotation group: Pitch, Roll, Rtn) between the two systems, the total time taken from patient set-up to just before IGRT, and exposure dose were measured and compared respectively with the RandoPhantom. Results: the set-up error in the phantom and patient was less than 1mm in the translation group and less than 1.5° in the rotation group, and the RMS values of all axes except the Rtn value were less than 1mm and 1°. The time taken to correct the set-up error in each system was an average of 256±47.6sec for IGRT using CBCT and 84±3.5sec for ExacTrac, respectively. Radiation exposure dose by IGRT per treatment was measured at 37 times higher than ExacTrac in CBCT and ExacTrac at 2.468mGy and 0.066mGy at Oral Mucosa among the 7 measurement locations in the head and neck area. Conclusion: Through 6D online automatic positioning between the CBCT and ExacTrac systems, the set-up error was found to be less than 1mm, 1.02°, including the patient's movement (random error), as well as the systematic error of the two systems. This error range is considered to be reasonable when considering that the PTV Margin is 3mm during the head and neck IMRT treatment in the present study. However, considering the changes in target and risk organs due to changes in patient weight during the treatment period, it is considered to be appropriately used in combination with CBCT.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2218-2229
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• 2015

Recently Wi-Fi Alliance defined Wi-Fi direct, which can communicate through a direct connection between the mobile device anytime, anywhere. In Wi-Fi direct, all devices are categorized by group of owner (GO) and client. Since portability is emphasized in Wi-Fi direct devices, it is essential to control the energy consumption of a device very efficiently. In order to avoid unnecessary power consumed by GO, Wi-Fi direct standard defines two power management schemes: Opportunistic power saving scheme and Notice Of Absence (NOA) scheme. But, these two schemes do not consider the traffic pattern, so we cannot expect high energy efficiency. In this paper, we suggest an algorithm to enhance the energy efficiency of Wi-Fi direct power saving, considering the characteristics of multimedia video traffic. Proposed algorithm utilizes the statistical distribution for the size of video frames and adjusts the length of awake interval dynamically. Also, considering the inter-dependency among video frames, the proposed algorithm assigns priorities to video frames and ensures that a video frame with high priority is transmitted with higher probability than other frames with low priority. Simulation results shows that the proposed method outperforms the traditional NOA in terms with average delay and energy efficiency.

• Journal of Digital Convergence
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• v.12 no.10
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• pp.317-327
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• 2014

To improve the efficiency of wireless channel, IEEE 802.11ac uses the DL MU-MIMO MAC scheme through which an AP transmits multiple frames to different mobile nodes simultaneously. IEEE 802.11ac DL MU-MIMO MAC needs a new step, called as TXOP sharing, between legacy IEEE 802.11n DL SU-MIMO's two operations, the obtaining an EDCA TXOP and the transmitting multiple frames for EDCA TXOP. In the TXOP sharing operation, both wireless channel destinations and frames transmitted for its TXOP period should are determined. So this paper deals with the TXOP sharing for improving IEEE 802.11ac MAC performance. However, the EDCA priority based method mentioned by IEEE 802.11ac standard document not fair among the buffers and the frames of buffers, and occurs in high_loss rate and high_delay about specific buffers. In this paper, we propose a new scheme of the TXOP sharing with sequencing p-AC, s-AC in similar properties, and all S-AC. This method provides a differentiated service without damage of EDCA characteristics.

• Journal of Intelligence and Information Systems
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• v.18 no.2
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• pp.19-28
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• 2012

After the internet era, we are moving to the ubiquitous society. Nowadays the people are interested in the multimodal interaction technology, which enables audience to naturally interact with the computing environment at the exhibitions such as gallery, museum, and park. Also, there are other attempts to provide additional service based on the location information of the audience, or to improve and deploy interaction between subjects and audience by analyzing the using pattern of the people. In order to provide multimodal interaction service to the audience at the exhibition, it is important to distinguish the individuals and trace their location and route. For the location tracking on the outside, GPS is widely used nowadays. GPS is able to get the real time location of the subjects moving fast, so this is one of the important technologies in the field requiring location tracking service. However, as GPS uses the location tracking method using satellites, the service cannot be used on the inside, because it cannot catch the satellite signal. For this reason, the studies about inside location tracking are going on using very short range communication service such as ZigBee, UWB, RFID, as well as using mobile communication network and wireless lan service. However these technologies have shortcomings in that the audience needs to use additional sensor device and it becomes difficult and expensive as the density of the target area gets higher. In addition, the usual exhibition environment has many obstacles for the network, which makes the performance of the system to fall. Above all these things, the biggest problem is that the interaction method using the devices based on the old technologies cannot provide natural service to the users. Plus the system uses sensor recognition method, so multiple users should equip the devices. Therefore, there is the limitation in the number of the users that can use the system simultaneously. In order to make up for these shortcomings, in this study we suggest a technology that gets the exact location information of the users through the location mapping technology using Wi-Fi and 3d camera of the smartphones. We applied the signal amplitude of access point using wireless lan, to develop inside location tracking system with lower price. AP is cheaper than other devices used in other tracking techniques, and by installing the software to the user's mobile device it can be directly used as the tracking system device. We used the Microsoft Kinect sensor for the 3D Camera. Kinect is equippedwith the function discriminating the depth and human information inside the shooting area. Therefore it is appropriate to extract user's body, vector, and acceleration information with low price. We confirm the location of the audience using the cell ID obtained from the Wi-Fi signal. By using smartphones as the basic device for the location service, we solve the problems of additional tagging device and provide environment that multiple users can get the interaction service simultaneously. 3d cameras located at each cell areas get the exact location and status information of the users. The 3d cameras are connected to the Camera Client, calculate the mapping information aligned to each cells, get the exact information of the users, and get the status and pattern information of the audience. The location mapping technique of Camera Client decreases the error rate that occurs on the inside location service, increases accuracy of individual discrimination in the area through the individual discrimination based on body information, and establishes the foundation of the multimodal interaction technology at the exhibition. Calculated data and information enables the users to get the appropriate interaction service through the main server.

• Journal of Korean Academy of Nursing
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• v.23 no.3
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• pp.467-486
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• 1993

Today, more chronically ill and handicapped people are being cared for at home by a family member caregiver. The task of caring for a family momber may mean that the caregiver has less time and money and more work which may result in increased fatigue and symptoms of illness. This study was done to examine the well-being of family caregivers. Fifty three family caregivers were interviewed. Concepts were measured using existing tools and included : Burden(25 item 5 point scale), Social sup-port (21 item 7 point scale), Health status defined by a symptom checklist(48 item S point scale), and Well -being defined by a quality of life scale (14 item 7 point scale) and caregiving activities. Data collection was done by interview and Q-sort. Social support and well - being were positively correlated as were symptoms and burden. Symptoms and burden were negatively correlated with social support and well-being. Items on the quality of life scale had a mean score range from 3.09 to 4.96. Quality of life related to income was lowest (3.09) but the desire to use more money for the patient was rated 2.90 on the burden scale where the item means ranged from 0.73 to 3.55. The high mean of 3.55 was for obligation to give care and the low 0.73 was (or not feeling that this was helping the patient. Mean scores for symptoms ranged from 0.26 to 2.15 with the 2.15 being for “worry about all the things that have to be done.” Over half of the patients were dependent for help with some activities of daily living. The caregivers reported doing an average of 3.40 out of five patient care activities including bathing (77.4%), shampooing (67.9%), and washing face and hands (49.1％), and 3.74 out of seven home maintenance activities including laundry (98.1％), cooking (83.0%), and arranging bed-ding(75.5%). The caregivers reported their spouse as one of the main sources of social support, including in times of loneliness and anger The mean score for loneliness as burden was 2.15 and ranked fourth and 31 (58.5％) of the sample reported being lonely recently and not being satisfied with the support received. Similarly anger caused by the patient was given a mean score of 2.13, and anger was reported to have been present recently by 38 (71.7%) of the sample and satis-faction with the support given was low. Having someone to help deal with anger ranked twelfth out of 21 items on the social support scale and had a mean score of 3.98 (range 3.49 to 5.98). Spouses were reported as a major source of social support but the fact that 50% of the caregivers were caring for a spouse, may account for the quality of this source of social support having been affected. These caregivers faced the same problems as others at the same stage of life. but because of the situation, there was a strain on their resources, particularly financial and social. In conclusion it was found that burden is correlated negatively to quality of life and positively to symptoms, but in this sample, symptoms and bur-den were scored relatively low. Does this indicate that the caregivers accept caregiving as part of their destiny and accept the quality of their lives with burden and symptoms just being a part of caregiving\ulcorner Does the correlation between the bur-den and symptoms indicate they are a measure of the same phenomenon or that the sample was of a more mobile, less burdened group of caregivers\ulcorner Quality of life was the one variable that was significant in explaining the varience on burden. Further study is needed to validate the conclusions found in this study but they indicate a need for nurses to ap-proach these caregivers with a plan tailored to each individual situation and to give consideration to interventions directed at improving quality of life and expanding social support networks for those caring for spouses.