• The KIPS Transactions:PartB
• /
• v.11B no.3
• /
• pp.303-308
• /
• 2004

The Gabor cosine and sine transform can be applied to image and video compression algorithm by representing image frequency components locally The computational complexity of forward and inverse matrix transforms used in the compression and decompression requires O($N^3$)operations. In this paper, the length of basis functions is truncated to produce a sparse basis matrix, and the computational burden of transforms reduces to deal with image compression and reconstruction in a real-time processing. As the length of basis functions is decreased, the truncation effects to the energy of basis functions are examined and the change in various Qualify measures is evaluated. Experiment results show that 11 times fewer multiplication/addition operations are achieved with less than 1% performance change.

• Wind and Structures
• /
• v.14 no.4
• /
• pp.337-357
• /
• 2011

The collection of wind speed time series by means of digital data loggers occurs in many domains, including civil engineering, environmental sciences and wind turbine technology. Since averaging intervals are often significantly larger than typical system time scales, the information lost has to be recovered in order to reconstruct the true dynamics of the system. In the present work we present a simple algorithm capable of generating a real-time wind speed time series from data logger records containing the average, maximum, and minimum values of the wind speed in a fixed interval, as well as the standard deviation. The signal is generated from a generalized random Fourier series. The spectrum can be matched to any desired theoretical or measured frequency distribution. Extreme values are specified through a postprocessing step based on the concept of constrained simulation. Applications of the algorithm to 10-min wind speed records logged at a test site at 60 m height above the ground show that the recorded 10-min values can be reproduced by the simulated time series to a high degree of accuracy.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.13 no.1
• /
• pp.57-62
• /
• 2009

Purpose: Brain SPECT study is more sensitive to motion than other studies. Especially, when applying 1-day subtraction method for Diamox SPECT, it needs shorter study time in order to prevent reexamination. We were required to have new study condition and analysing method on dual detector system because triple head camera in Seoul National University Hospital is to be disposed. So we have tried to increase image quality and make the dual and triple head to have equivalent study time by using a new analysing program. Materials and Methods: Using IEC phantom, we estimated contrast, SNR and FWHM. In Hoffman 3D brain phantom which is similar with real brain, we were on the supposition that 5% of injected doses were distributed in brain tissue. To compare with existing FBP method, we used fan-beam collimator. And we applied 15 sec, 25 sec/frame for each SEPCT studies using LEHR and LEUHR. We used OSEM2D and Onco-flash3D reconstruction method and compared reconstruction methods between applied Gaussian post-filtering 5mm and not applied as well. Attenuation correction was applied by manual method. And we did Brain SPECT to patient injected 15 mCi of $^{99m}Tc$-HMPAO according to results of Phantom study. Lastly, technologist, MD, PhD estimated the results. Results: The study shows that reconstruction method by Flash3D is better than exiting FBP and OSEM2D when studied using IEC phantom. Flowing by estimation, when using Flash3D, both of 15 sec and 25 sec are needed postfiltering 5 mm. And 8 times are proper for subset 8 iteration in Flash3D. OSEM2D needs post-filtering. And it is proper that subset 4, iteration 8 times for 15sec and subset 8, iteration 12 times for 25sec. The study regarding to injected doses for a patient and study time, combination of input parameter-15 sec/frame, LEHR collimator, analysing program-Flash3D, subset 8, iteration 8times and Gaussian post-filtering 5mm is the most appropriate. On the other hands, it was not appropriate to apply LEUHR collimator to 1-day subtraction method of Diamox study because of lower sensitivity. Conclusions: We could prove that there was also an advantage of short study time effectiveness in Dual camera same as Triple gamma camera and get great result of alternation from existing fan-beam collimator to parallel collimator. In addition, resolution and contrast of new method was better than FBP method. And it could improve sensitivity and accuracy of image because lesser subjectivity was input than Metz filter of FBP. We expect better image quality and shorter study time of Brain SPECT on Dual detector system.

• The Journal of Society for e-Business Studies
• /
• v.15 no.4
• /
• pp.1-19
• /
• 2010

Recently, it is necessary to process real time sensor data, which is generated from ubiquitous environments. Data, which are written by XML, are small, but, large volumes of data. Therefore, weneed to use an efficient method for processing a large amount of it. An XQuery has two types for sensor data: one is to get sensor identification and value from sensor data; the other is restructuring for user's convenience. Existing XQuery engines don't have efficient method for batch processing of sensor data. This paper proposed the twig query processing over reverse path summary, and we developed and applied restructuring batch processing method for real time processing of a large amount of sensor data. Finally, we do performance evaluation using XMark and RFID EPC data, and comparison analysis with MonetDB/XQuery and Berkeley DB XML.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.1
• /
• pp.256-263
• /
• 2021

This paper studies the problems and improvements of government real estate policies. Moon Jae-in government shifted toward regulation and pledge to curb the tax imposed by speculators. It strengthened regulations on reconstruction and bank loans rather than supply, and raised capital gains taxes. As the government implemented measures, emphasizing political logic rather than the economy, the market is unstable and the economy is in a recession. Land has increased the vicious cycle of problems due to population growth, industrialization, urbanization, and wealth growth. Mis-established land policies not only accelerate land prices, but also accelerate the use of disordered land and lead to disruptions in the trading order. In addition, real estate is so difficult to recover from the land problem that it is difficult to contain water that has been spilled once. This is called the irreversible nature of land. Once the land price rises, it is difficult to regain control and reckless development leads to the destruction of the ecosystem, making it difficult to return. This is why such a complex real estate issue should not be implemented as if it were a punishment in a short period of time with government policies. This paper aims to examine the problems of real estate policies and to examine ways to improve them.

• Journal of Broadcast Engineering
• /
• v.27 no.2
• /
• pp.207-215
• /
• 2022

The latest volumetric technology's high geometrical accuracy and realism ensure a high degree of correspondence between the real object and the captured 3D model. Nevertheless, since the 3D model obtained in this way constitutes a sequence as a completely independent 3D model between frames, the consistency of the model surface structure (geometry) is not guaranteed for every frame, and the density of vertices is very high. It can be seen that the interconnection node (Edge) becomes very complicated. 3D models created using this technology are inherently different from models created in movie or video game production pipelines and are not suitable for direct use in applications such as real-time rendering, animation and simulation, and compression. In contrast, our method achieves consistency in the quality of the volumetric 3D model sequence by linking re-meshing, which ensures high consistency of the 3D model surface structure between frames and the gradual deformation and texture transfer through correspondence and matching of non-rigid surfaces. And It maintains the consistency of volumetric 3D model sequence quality and provides post-processing automation.

• Journal of the HCI Society of Korea
• /
• v.2 no.2
• /
• pp.1-9
• /
• 2007

In this paper, we propose a reconstruction technique of the lost hair region for 3D human actor modeling. An active depth sensor system can simultaneously capture both color and geometry information of any objects in real-time. However, it cannot acquire some regions whose surfaces are shiny and dark. Therefore, to get a natural 3D human model, the lost region in depth image should be recovered, especially human hair region. The recovery is performed using both color and depth images. We find out the hair region using color image first. After the boundary of hair region is estimated, the inside of hair region is estimated using an interpolation technique and closing operation. A 3D mesh model is generated after performing a series of operations including adaptive sampling, triangulation, mesh smoothing, and texture mapping. The proposed method can generate recovered 3D mesh stream automatically. The final 3D human model allows the user view interaction or haptic interaction in realistic broadcasting system.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.46 no.1
• /
• pp.32-40
• /
• 2009

In this paper, we proposed an reconstruction algorithm of transmitted frames from displayed image on video terminal. For image quality assessment of the video streaming in the wireless network, we need information of the image that is transmitted to the end-user's device. Generally, subjective methods are widely used to evaluate the image quality by human beings because it is difficult to extract the transmitted image from the end-user's device. This paper presents an image reconstruction algerian based on the displayed image in video terminal for the extraction of the transmitted image. In the proposed method, we acquired the displayed image on video terminal using the camera. Camera-acquired images exhibit geometric and color distortions caused by characteristics of cameras and display devices. Therefore we correct the geometric distortion by exploiting the homography and color distortion by pre-computed look-up table. The experimental results show that the proposed measurement system yields promising estimation performance in terms of PSNR of $27{\sim}28dB$. We also carried out performance evaluation of the proposed method in terms of EPSNR and the quality of the estimated images by the proposed algerian was in fairly good range of MOS test scale.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.43 no.3 s.309
• /
• pp.8-15
• /
• 2006

Obstacle detection is an important task for many mobile robot applications. The methods using stereo vision and optical flow are computationally expensive. Therefore, this paper presents a vision-based obstacle detection method using only two view images. The method uses a single passive camera and odometry, performs in real-time. The proposed method is an obstacle detection method using 3D reconstruction from taro views. Processing begins with feature extraction for each input image using Dr. Lowe's SIFT(Scale Invariant Feature Transform) and establish the correspondence of features across input images. Using extrinsic camera rotation and translation matrix which is provided by odometry, we could calculate the 3D position of these corresponding points by triangulation. The results of triangulation are partial 3D reconstruction for obstacles. The proposed method has been tested successfully on an indoor mobile robot and is able to detect obstacles at 75msec.

• Archives of Craniofacial Surgery
• /
• v.13 no.1
• /
• pp.41-45
• /
• 2012

Purpose: Fibular osteocutaneous free flap is the procedure of choice for mandibular reconstruction. However, the anatomic consistency and the reliability of the skin paddle have been considered to be questionable and the utilization of the fibular osteocutaneous free flap can be challenging for the inexperienced surgeon. Preoperative computed tomography (CT) angiography can support revolutionary help with the operator design of the fibular osteocutaneous flap. The purpose of this article is to share the valuable experience of support with preoperative CT angiography. Methods: Three consecutive patients, who needed mandibular reconstruction, were treated with fibular osteocutaneous free flap. Each of the patients had undergone lower extremity CT angiography before the surgery. The CT angiographies were scrupulously investigated to calculate the locations and the tracts of the peroneal artery perforators. We compared the findings of the CT angiography with those of the real operation. Results: The information about the perforators was sufficiently matched with the findings of the operation. With the use of preoperative CT angiography, we were able to achieve confident performance during operation, shortening of operation time, and fine outcomes with a no flap failure. Conclusion: The CT angiography of lower extremity can provide reliable information of the perforators of the fibular osteocutaneous free flap.