• Progress in Medical Physics
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• v.9 no.4
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• pp.201-206
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• 1998

IMRT optimization method on multiple slice has been developed by using gradient based algorithm. On about 10-30 CT slices including treatment region of a patient, dose optimization has been performed slice by slice to meet the condition that each organ should be exposed below maximum tolerable doses and that the tumor dose within the range of 100$\pm$5 %. Field size was limited to 8$\times$8 cm$^2$ and in this condition, beam divergence was not taken into account to calculate dose distribution. Total dose distribution was calculated by superposing each beamlet whose dose distribution had been precalculated. In order to investigate beam number dependency, dose optimization was performed for one, three, five, seven, and nine coplanar beams and then each optimization index was evaluated. It is found that optimization time was proportional to number of slices to be optimized, and the most efficient plan was obtained from the case of three-to-seven incident beams with respect to calculation time and optimization index. In conclusion, dose optimization of multiple slice was able to be obtained by repeating dose optimization of single slice under condition that the beam size is not too large to ignore beam divergence. And it turns out that result of dose optimization was so sensitive to the position of isocenter that some method to optimize isocenter position is needed to improve it.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.933-939
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• 2019

The purpose of this study is to provide basic clinical data by evaluating images, measuring absorbed dose and effective dose by using high resolution CT and low dose CT by using anthropomorphic chest phantom and glass dosimeter. Tissue dose was measured by inserting a glass dosimeter into the anthropomorphic chest phantom. A 64-slice CT system (SOMATOM Sensation 64, Siemens AG, Forchheim, Germany) and CARE Dose 4D were used, and the parameters of the high resolution CT were 120 kVp, Eff. Scan parameters of mAs 104, scan time 7.93 s, slice 1.0 mm (Acq. 64 × 0.6 mm), convolution kernel (B60f sharp) were used, and low dose CT was 120 kVp, Eff. mAs 15, scan time 7.41 s, slice 3.0 mm (Acq. 64 × 0.6 mm), scan of convolution kernel B50f medium sharp. CTDIvol was measured at 8.01 mGy for high resolution CT and 1.18 mGy for low dose CT. Low dose CT scans showed 85.49% less absorbed dose than high resolution CT scans.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.332-336
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• 2008

Red ginseng is classified according to outer form and the quality of internal tissue, and red ginseng below third grade can't be sold. Also there are many differences in price according to grade. So if inferior Red ginseng is sold, economic loss and claim take place. This research is done conducted to investigate the possibility of the non-destruction internal tissue investigation of red ginseng. It is observed and compared that MR image after getting MR image agrees with real cutting side in 10-13% water content of red ginseng. The MR image can be obtained to see the internal section of red ginseng with equal condition of time, temperature and slice thickness in spin echo pulse sequence. The MR signal of red ginseng is very weak, because it contains low water density. So it takes about 30 minutes with the measurement of single point image (SPI). But the suitable time to distinguish internal tissues is about 9 seconds in TE (Echo Time) 2.23 ms, TR (Repetition Time) 150ms. The image to discriminate internal tissues in 9 seconds can be obtained when slice thickness is 10 mm with changes of 3, 5, 10 mm. The image obtained after 30 minutes' boiling of 55 degrees has clearer image than that of normal temperature. It is thought that MR signal is stronger through active motion of water particles as temperature increases. With this method MR image of red ginseng can be obtained and characteristics of internal tissues can be observed in such a short time.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.4
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• pp.267-273
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• 2011

In this paper, we proposed the method to detect brain tumor region in MR images. Our method is composed of 3 parts, detection of tumor slice, detection of tumor region and tumor boundary detection. In the tumor slice detection step, a slice which contains tumor regions is distinguished using symmetric analysis in 3D brain volume. The tumor region detection step is the process to segment the tumor region in the slice distinguished as a tumor slice. And tumor region is finally detected, using spatial feature and symmetric analysis based on the cluster information. The process for detecting tumor slice and tumor region have advantages which are robust for noise and requires less computational time, using the knowledge of the brain tumor and cluster-based on symmetric analysis. And we use the level set method with fast marching algorithm to detect the tumor boundary. It is performed to find the tumor boundary for all other slices using the initial seeds derived from the previous or later slice until the tumor region is vanished. It requires less computational time because every procedure is not performed for all slices.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1449-1453
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• 1987

A microprogrammable Bit Slice Sinal Processor for image processing is implemented. Processing speed is increased by the parallelism in horizontal microprogram using 120bits microcode, pipelined architecture, 2 bank memory switching that interfaces with the Host through DMA, a variable clock control, overflow checking H/W,look-up table method and cache memory. With this processor, a DCT algorithm which uses 2-D FFT is performed. The execution time for $512{\times}512{\times}8$ image is 12 sec when 16 bit operation is runned, and the recovered image has acceptable quality with MSE 0.276%.

• Journal of Korea Multimedia Society
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• v.6 no.6
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• pp.991-999
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• 2003

In this paper, we proposed image acquisition techniques that can reflect anatomical airway information lot breath change by EBCT Also, we proposed new method to detect automatically boundary of inner airway for acquired slice images using this image acquisition technology. We confirmed that new method detects boundary of inner airway effectively through computer simulation that apply image data about each slice position of airway. And, we could see change for cross section area of inner airway by time change. Therefore, we think that proposed method can utilize on quantitative analysis in clinical field.

• Journal of Information Processing Systems
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• v.6 no.4
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• pp.537-552
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• 2010

Software Debugging is the most time consuming and costly process in the software development process. Many techniques have been proposed to isolate different faults in a program thereby creating separate sets of failing program statements. Debugging in parallel is a technique which proposes distribution of a single faulty program segment into many fault focused program slices to be debugged simultaneously by multiple debuggers. In this paper we propose a new technique called Faulty Slice Distribution (FSD) to make parallel debugging more efficient by measuring the time and labor associated with a slice. Using this measure we then distribute these faulty slices evenly among debuggers. For this we propose an algorithm that estimates an optimized group of faulty slices using as a parameter the priority assigned to each slice as computed by value of their complexity. This helps in the efficient merging of two or more slices for distribution among debuggers so that debugging can be performed in parallel. To validate the effectiveness of this proposed technique we explain the process using example.

• Journal of the korean society of oceanography
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• v.31 no.2
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• pp.64-74
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• 1996

Numerical experiments of OAT (Ocean Acoustic Tomography) are carried out in the East Sea of Korea where the canonical ocean has been perturbed by a mesoscale warm eddy and a thermal front. In order to estimate the horizontal and vertical structure of water temperature of the perturbed ocean, the experimental area is divided into 16 cells with 8 pairs of sources and receivers for a horizontal slice and the water column is divided into 8 layers for a vertical slice. The inversely estimated temperature field by using SVD (Singular Value Decomposition) method reveals the eddy and frontal structure clearly. The rms errors of the two horizontal slices are less than $0.4^{\circ}C$ and $1.7^{\circ}C$ at 400 m and 200 m depths, respectively, while the error in the vertical slice is less than $1.0^{\circ}C.$ For better estimation of temperature by OAT method, particularly for the East Sea, a range-dependent ray model should be used to solve the forward problem. At the same time, improvement in computing the refracted ray path between vertical layers is required to obtain more accurate travel time information. The results of the present experiment give rise to a possibility of application of OAT in remote sensing of the ocean thermal structure.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.6
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• pp.848-852
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• 2011

The aim of our study was to develop drying process of apple slice. Quality characteristics of apple slices dried by hot-air and freeze drying after osmotic dehydration was investigated in different sucrose solution (20, 40, $60^{\circ}Brix$) and steeping time (2, 4, 8 hours). The weight of apple slice before and after osmotic dehydration was measured for characteristic of mass transfer. Consequently, osmotic dehydration increases weight reduction, water loss and solid gain of apple slice as the concentration of the sucrose solution and steeping time increased. Moisture contents of apples slices dried hot-air and freeze were about 3 to 7%. Hunter color L, a, b value was lower than non-treatment to osmotic dehydration of apple slice. In hot-air drying, L value decreased as the concentration of the sucrose solution and steeping time increased. The hardness increased as the concentration of the sucrose solution and steeping time increased. Contents of monosaccharide (glucose, fructose) decrease by osmotic dehydration but sucrose increased. In comparison with hot-air drying, freeze drying was high in contents of free sugar.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.135-135
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• 2002

Purpose： To assess diagnostic accuracy of dynamic contrast enhanced MR mammography in differentiating between benign and malignant lesions. Materials and methods： Ninety-three patients with suspicious mammographic, sonographic or palpable findings underwent pre- or postoperative contrast-enhanced MR imaging of breast using three dimensional fast low-angle shot (3D FLASH) sequence (16/4 msec［repetition time / echo time］, 20 flip angle, 3mm slice thickness with no slice gap, 256 by 256 in-plane matrix) covering whole breasts. T1 weighted images were obtained before and after bolus administration of gadopentetate dimeglumine (0.15 mmol/kg). Subtraction images and time-signal intensity curves of region of interest were obtained sequentially and correlated with pathologic diagnoses of lesions.