• Journal of Broadcast Engineering
• /
• v.20 no.3
• /
• pp.414-420
• /
• 2015

The quality of depth images is important in the 3D video system to represent complete 3D contents. However, the original depth image from a depth camera has a low resolution and a flickering problem which shows vibrating depth values in terms of temporal meaning. This problem causes an uncomfortable feeling when we look 3D contents. In order to solve a low resolution problem, we employ 3D warping and a depth weighted joint bilateral filter. A temporal mean filter can be applied to solve the flickering problem while we encounter a residual spectrum problem in the depth image. Thus, after classifying foreground andbackground regions, we use an upsampled depth image for a foreground region and temporal mean image for background region.Test results shows that the proposed method generates a time consistent depth video with a high resolution.

• Annals of Clinical Neurophysiology
• /
• v.5 no.2
• /
• pp.177-180
• /
• 2003

Background and Objectives: A nerve conduction study (NCS) has been known as a useful method to evaluate the therapeutic effect of operation in carpal tunnel syndrome (CTS). To evaluate the temporal relationship between symptomatic and electrophysiological improvement, we compared the preoperative symptoms and electrophysiological results with postoperative those. Methods: We analyzed the NCS changes before and after minimal release of carpal tunnel in 26 patients (34 hands) with CTS. The time of postoperative symptomatic changes, postoperative electrophysiological changes and temporal relationship between symptomatic and electrophysiological changes were evaluated. Results: The mean age was $49{\pm}13$ years. The proportion of males to female was 8 and 92 percent. The median interval days between date of operation and those of postoperative NCS was 28.5 days. Postoperative symptoms improved in 17 hands, slightly improved in 13 hands, and have not changed in 4 hands. Electrophysiological improvements after operation were observed in 26 hands, and mostly appeared within 2 months. Symptomatic relief accompanied with electrophysiological improvement reported in 13 hands (50%). Moreover, the four hands with symptom, not relieved by decompression, showed electrophysiological improvement. Conclusions: In this study, electrophysiological improvement was in consistency with symptomatic relief to some extent, but we got the result of disagreement between electrophysiological and symptomatic improvement.

• Korean Journal of Remote Sensing
• /
• v.35 no.4
• /
• pp.545-560
• /
• 2019

Unlike other critical forest diseases, pine pitch canker in Korea has shown rather mild symptoms of partial loss of crown foliage and leaf discoloration. This study used high-resolution satellite images to detect and monitor canopy decline by pine pitch canker. To enhance the subtle change of canopy reflectance in pitch canker damaged tree crowns, multi-temporal analysis was applied to two KOMPSAT multispectral images obtained in 2011 and 2015. To assure the spectral consistency between the two images, radiometric corrections of atmospheric and shadow effects were applied prior to multi-temporal analysis. The normalized difference vegetation index (NDVI) of each image and the NDVI difference (${\Delta}NDVI=NDVI_{2015}-NDVI_{2011}$) between two images were derived. All negative ΔNDVI values were initially considered any pine stands, including both pitch canker damaged trees and other trees, that showed the decrease of crown foliage from 2011 to 2015. Next, $NDVI_{2015}$ was used to exclude the canopy decline unrelated to the pitch canker damage. Field survey data were used to find the spectral characteristics of the damaged canopy and to evaluate the detection accuracy from further analysis.Although the detection accuracy as assessed by limited number of field survey on 21 sites was 71%, there were also many false alarms that were spectrally very similar to the damaged canopy. The false alarms were mostly found at the mixed stands of pine and young deciduous trees, which might invade these sites after the pine canopy had already opened by any crown damages. Using both ${\Delta}NDVI$ and $NDVI_{2015}$ could be an effective way to narrow down the potential area of the pitch canker damage in Korea.

• International Journal of Highway Engineering
• /
• v.17 no.6
• /
• pp.117-126
• /
• 2015

PURPOSES : This study prioritizes potential technology for establishing a safe work zone environment on roadways. We consider almost all conceivable technologies that enable mitigation of unexpected accidents for both road workers and drivers. METHODS : This study suggests a methodology to set the priority of potential technology for establishing a safe work zone environment by using the analytical hierarchy process (AHP). For this purpose, the AHP structure was first developed. Thereafter, a web-based survey was conducted to collect experts' opinions. Based on the survey results, weights associated with the relevant criteria of the developed structure were estimated. With the consistency index (CI) and consistency ratio (CR), we verified the estimated weights. In addition, a sensitivity analysis was performed to confirm whether the estimated weights were reliable. We finally proposed the priority for potential technology for establishing a safe work zone environment on roadways. RESULTS : In the first level, safety technology has the highest priority, and real-time information delivery for work zone, hazard warning for drivers, and temporal automated operation for traffic facilities were selected in the second level of hierarchy. CONCLUSIONS : The results imply that establishing the priority will be useful to establish a future road map for improving the work environment for road workers and drivers by employing appropriate protection facilities and developing safety systems.

• Journal of Digital Contents Society
• /
• v.19 no.4
• /
• pp.757-770
• /
• 2018

Foreground extraction is the most significant step in thermal imaging based surveillance systems. This step needs to be efficient in terms of time and memory consumption in order for the system to provide real time results but usually this efficiency reciprocates with the accurateness of the ROI detection. In this study, novel selective histogram bins based two background & foreground separation approaches for thermal videos processing have been proposed which exploit the temporal-consistency property of the thermal images in a given environment and can save over 80% memory than their simplest counterpart temporal median filtering.

• The Journal of the Korea Contents Association
• /
• v.7 no.6
• /
• pp.9-21
• /
• 2007

In this paper, the hybrid methods are suggested, which use the direction angle information to present running trajectory and track the past locations through a small amount of vehicle's location information. In order to prove the effectiveness of the new technique suggested here, vehicle's location information are collected by running the vehicles moving objects under various conditions. Using the location informations and direction angle information collected with time intervals, the vehicl e's location information is abstracted, compared and analyzed. and I have proved that the suggested techniques are more effective by comparing them with others in various methods such as GPS TrackMaker, difference image techniques, consistency comparison, quantity comparison, vehicle's running distances and so on.

• Korean Journal of Applied Biomechanics
• /
• v.31 no.3
• /
• pp.199-204
• /
• 2021

Objective: The purpose of this study was to present a new idea of methodology to evaluate Poomsae performance using inertial measurement unit (IMU) sensors in terms of signal processing techniques. Method: Ten collegian Taekwondo athletes, consisting of five Poomsae elite athletes (age: 21.4 ± 0.9 years, height: 168.4 ± 11.3 cm, weight: 65.0 ± 10.6 kg, experience: 12 ± 0.7 years) and five breaking demonstration athletes (age: 21.0 ± 0.0 years, height: 168.4 ± 4.7 cm, weight: 63.8 ± 8.2 kg, experience: 13.0 ± 2.1 years), voluntarily participated in this study. They performed three different black belt Poomsae such as Goryeo, Geumgang, and Taebaek Poomsae repeatedly twice. Repeated measured motion data on the wrist and ankle were calculated by the methods of cosine similarity and Euclidean distance. Results: The Poomsse athletes showed superior performance in terms of temporal consistency at Goryeo and Taebaek Poomsae, cosine similarity at Geumgang and Taebaek Poomsae, and Euclidian distance at Geumgang Poomsae. Conclusion: IMU sensor would be a useful tool for monitoring and evaluating within-subject temporal variability of Taekwondo Poomsae motions. As well it distinguished spatiotemporal characteristics among three different Poomsae.

• Journal of KIISE:Information Networking
• /
• v.31 no.5
• /
• pp.460-468
• /
• 2004

Quality of Service (QoS)-constrained policy has an advantage to guarantee QoS requirements requested by users. Quorum systems can ensure the consistency and availability of replicated data despite the benign failure of data repositories. We propose a Quorum based resource management scheme, which includes a system resource and network resource, both of which can satisfy the requirements of application QoS. We also propose the resource reconfiguration algorithm based on temporal execution time estimation method. Resource reconfiguration means that reshuffling the current available resource set for maintaining the quality level of the resources. We evaluate the effectiveness of resource reconfiguration mechanism with a Heart Hemodynamics analysis. Our approach shows the increase of the stability of execution environment as well as decrease the completion time compare to the method that is not adapted the resource reconfiguration.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.48 no.5
• /
• pp.55-62
• /
• 2011

In this paper, a temporal color and luminance variation suppression algorithm for a digital video sequence is proposed by considering time-varying light source. When a video sequence is sampled with the periodically emitting illuminant and with a short exposure time, the color rolling phenomenon occurs, where the color and the luminance of the image periodically change from field to field. In conventional signal processing techniques, the luminance variation remaining in the resultant video sequence degrades the constancy of the image sequence. In the proposed method, we obtain video sequences with constant luminance and color by compensating for the inter-field luminance variation. Based on a motion detection technique, the amount of the luminance variation for each channel is estimated on the background of the sequence without the effects of moving objects. The experimental results clearly show that our strategy efficiently estimated the illuminant change without being affected by moving objects, and the variations were efficiently reduced.

• Journal of Korean Society for Atmospheric Environment
• /
• v.27 no.6
• /
• pp.650-662
• /
• 2011

The statistical tools such as empirical orthogonal function (EOF), and singular value decomposition (SVD) have been applied to analyze the characteristic of air pollutant over southeast Asia as well as to evaluate Zimeke's tropospheric column ozone (ZTO) determined by tropospheric residual method. In this study, we found that the EOF and SVD analyses are useful methods to extract the most significant temporal and spatial pattern from enormous amounts of satellite data. The EOF analyses with OMI $NO_2$ and OMI HCHO over southeast Asia revealed that the spatial pattern showed high correlation with fire count (r=0.8) and the EOF analysis of CO (r=0.7). This suggests that biomass burning influences a major seasonal variability on $NO_2$ and HCHO over this region. The EOF analysis of ZTO has indicated that the location of maximum ZTO was considerably shifted westward from the location of maximum of fire count and maximum month of ZTO occurred a month later than maximum month (March) of $NO_2$, HCHO and CO. For further analyses, we have performed the SVD analyses between ZTO and ozone precursor to examine their correlation and to check temporal and spatial consistency between two variables. The spatial pattern of ZTO showed latitudinal gradient that could result from latitudinal gradient of stratospheric ozone and temporal maximum of ZTO in March appears to be associated with stratospheric ozone variability that shows maximum in March. These results suggest that there are some sources of error in the tropospheric residual method associated with cloud height error, low efficiency of tropospheric ozone, and low accuracy in lower stratospheric ozone.