• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.109-112
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• 2004

The effect of auxiliary electrode on the discharge characteristics in AC PDP with long sustain-gap was investigated. The auxiliary electrode was placed between scan and common electrode. When the pulse was applied to the auxiliary electrode during sustain period, the luminance of Ne + 13%Xe gas-mixture discharge increased and the discharge current decreased. The auxiliary pulse plays a role of improving electron excitation efficiency. When the auxiliary pulse was applied during address period, the address discharge time lag of Ne + 13%Xe gas-mixture could be reduced remarkably.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.9
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• pp.7-11
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• 2007

The objective of this study is to evaluate the characteristics of a newly proposed high-speed drive method for the gray scale display for high-resolution plasma display panels(PDP). In the experiment it was found that the characteristics of gray scale display are not closely affected by a priming period below 50[${\mu}s$], the width of the priming period, and that it can be driven stably from the brightest sub-field to the darkest sub-field even though a priming discharge is applied to the 1 TV-field only once. Moreover, from the experimental result, the gray scale pattern of 8-bit and 9 sub-fields was stably displayed in the experimental PDP with scan pulses having the pulse width of 0.7[${\mu}s$]. An address voltage margin of about 25[V] and a sustain voltage margin of about 10[V] was obtained.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.107-109
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• 2016

In this paper, we address the TCP-over-WLAN performance problem that occurs during periodic active background scanning with which mobile devices discover available APs in the vicinity. We measure the impact of the scanning period on the TCP throughput and observe a significant performance degradation when the scan operation period is shortened. Our experimental analysis has identified the main cause of the problem, that is, the associated AP continues to send packets to the mobile device even when the device is not able to receive due to the scanning operation.

• Childhood Kidney Diseases
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• v.5 no.1
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• pp.30-35
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• 2001

Purpose : To evaluate tile frequency of urinary tract anomalies in male neonates less than 3 months old who presented with urinary tract infection(UTI) and to evaluate a appropriate imaging approach after first UTI. Materials and methods : During a period of 5 years from March 1994 to February 1999, 65 male infants less than 3months old(range: 4-92 days, mean: 43 days) with UTI were evaluated. Ultrasound(US) and Voiding cystourethrogram(VCUG) were done in 60 patients. Due to refusal and technological problem, 5 patients were missed. 99mTc-dimercaptosuccinic acid renal scan (99mTc-DMSA renal scan) was recommended to most patients but performed in 40 patients. Renal scan was performed at least 3 months later after urinary tract infection. Results : Urinary tract anomalies were found in 26 of 65 infants. Twenty-six had vesicoureteral reflux(VUR), two had both VUR and double ureter, two had both U and posterior urethral valve. In patients with VUR, eight had renal scar or renal atrophies. In case of renal scar or atrophy, grades of VUR were III or above. Conclusion : We suggest that US and VCUG should be routinely performed in infants(<3months)with first UTI. 99mTc-DMSA renal scan should be performed only when renal parenchymal damage was observed in US and VUR grade III or above in VCUG. (J. Korean Soc Pediatr Nephrol 5 : 30- 5, 2001)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.4
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• pp.292-300
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• 2004

Orbital blowout fractures are common consequence to blunt periorbital trauma. Pure orbital blowout fractures first occur at the weakest point of the orbital wall. Computed tomography(CT) is recognized to be the best imaging technique to evaluate orbital fractures. The extent and location of a blowout fractures in the CT scan were noted to have an effect on the clinical outcome. In the early posttraumatic period, the presence of significant enophthalmos is difficult to detect because of orbital edema. Early surgical intervention may improve the ultimate outcome because open reconstruction becomes more difficult if surgery is delayed. In this study, we evaluated isolated blowout fractures of the orbital floor by region-of-interest measurements from CT scans and their relationship to ophthalmologic findings. Six patients of the medial orbital wall fractures, eleven patients of the inferior orbital wall fractures, nineteen of the medial and the inferior orbital wall fractures confirmed by CT scan, were evaluated. The area of fracture and the volume of the displaced orbital tissue were determined from CT scan using linear measurements. Each of the calculated values for the area and the volume were compared with the degree of the enophthalmos, the diplopia, and the eyeball movement limitation to determine whether there was any significant relationship between them. The fracture area and the volume of the herniated orbital tissue were significantly positively correlated with the enophthalmos and the ocular motility limitation and not correlated with the diplopia. For the enophthalmos of 2mm or greater, the mean fracture area was 3.55{\pm}1.25cm^2$ and the volume of the herniated orbital tissue was $1.74{\pm}0.97cm^3$; for less than 2mm enophthalmos, $1.43{\pm}0.99cm^3$ and $0.52{\pm}0.49cm^3$, respectively. The enophthalmos of 2mm can be expected with $2.92cm^2$ of the fracture area and $1.40cm^3$ of the herniated orbital tissue. In conclusion, the enophthalmos of 2mm or more, which is a frequent indication for surgery. It can be expected when area of fracture is $2.92cm^2$ or more, or the volume of herniated orbital tissue is $1.40cm^3$ or more. And the CT scan using linear measurements has an application in the assessment of patients with blowout fractures and provides useful information in the posttraumatic evaluation of orbital fractures.

• The Journal of the Korea Contents Association
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• v.8 no.12
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• pp.236-245
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• 2008

The cancer patient who leads Bone scan and the PET study from in the nuclear medical study what is enforced with the link of early detection and the time which spreads, it will be able to accomplish a positive treatment with the data which presumes that time it researches a degree as cancer discovery initially and only difference of final period the bay it knows. The patient who receives a cancer decision it will be able to accomplish the necessary defense it will be able to delay the time in order, the maximum control the possibility of doing will be becomes the judgement. Cancer decision to initially the nuclear study and treatment it will be in parallel with effort and the investment which are constant and the schedule hour will elapse and to after difficulty some the case which comes to be negligent will be frequent and it will appear with him there to be a possibility of knowing, it will be caused by and the transfer of the cancer sell will be activity. It has a treatment objective and are to each medical treatment agency against and the medical treatment agency worker it will be able to overlook is not the portion is the private plan which needs a more positive disposal, it does.

• Advances in pediatric surgery
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• v.19 no.2
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• pp.57-65
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• 2013

The entity of negative appendectomies still poses a dilemma in chlidren. Focused computed tomography (CT) scanning has become the diagnostic test of choice in many hospitals. However, the impact of CT scans on the diagnosis in children is unknown exactly. The purpose of this study was to critically evaluate CT scans for the evaluation of acute appendicitis in children, to review utilization of this diagnostic test in our appendicitis population and to determine if diagnostic accuracy has improved. A retrospective analysis of efficacy of CT scan for diagnosis of appendicitis in children was conducted. Children undergoing appendectomy for acute appendicitis were reviewed from 2007 to 2012. Perforation and negative appendectomy (removal of a normal appendix) rates were determined by the final pathologic report. Statistical comparison were made using the $x^2$ test and significance was assigned at p < 0.05. Five hundred four appendectomies were performed. Mean age was $10.1{\pm}3.21$ years, and 62.7% were boys. Overall, 308 children (61.1%) underwent CT scanning, 100 (19.8%) had US performed, and 97 (19.2%) had no radiographic study. A pathologically normal appendix was removed in 8.7% (27 of 308) of CT patients, 9.0% (9 of 100) of US patients, and 11.3% (11 of 97) of patients without a study. The frequency of CT scanning increased from 29.7% (27 of 91) of all children in 2007 to 75.6% (59 of 78) in 2012, whereas utilization of US decreased from 30.8% (28 of 91) to 11.5% (9 of 78). During this time period the difference in the negative appendectomy rate did change significantly from 14% to 6%. Liberal use of CT scans in diagnosing appendicitis in children has resulted in a decreased negative appendectomy rate.

• Archives of Plastic Surgery
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• v.39 no.6
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• pp.631-635
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• 2012

Background The evaluation of a breast after breast reconstruction depends on a surgeon's subjective criteria. We used computed tomography (CT) scans to obtain an objective evaluation of the postoperative results by measuring the breast volume of patients who had undergone breast reconstruction using pedicled transverse rectus abdominis myocutaneous (TRAM) flaps. This research will help in the objective postoperative evaluation of reconstructed breasts, and also in the preoperative flap size designs. Methods A total of 27 patients underwent breast reconstruction using pedicled TRAM flaps after mastectomy from September 2007 to July 2010. Of these, 10 patients who were followed up and underwent CT scans 2 or more times during the follow-up period were included in this study. We evaluated the change in breast volume over time using CT scans, and the interval breast volume change between CT scans. Results All of the 10 patients' reconstructed breasts showed a volume decrease over time. The breast volume changes in the intervals between CT scans were as follows: 5.65% decrease between the first CT and second CT scan, 2.3% decrease between the second CT and third CT scan, (statistically significant) and 1.89% decrease between the third CT and forth CT scan. (not statistically significant). Conclusions This research shows the possibility of objectively evaluating the postoperative breast volume changes. The findings will be helpful in designing the size of TRAM flaps to use on defects after mastectomy. Based on these results, we should also closely observe the reconstructed breast volume for at least 2 years.

• Journal of Trauma and Injury
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• v.23 no.2
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• pp.142-150
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• 2010

Purpose: In this study, patients in whom two computed tomography (CT) scans had been obtained within 24 hours of injury were analyzed to determine the incidence, risk factors and clinical significance of a progressive intracerebral hematoma (PIH). Methods: Participants were 182 patients with a traumatic intracerebral hematoma and contusion who underwent a repeat CT scan within 24 hours of injury. Univarite and multivariate statistics were used to define growth (volume increase) and to examine the relationship between the risk factors and hemorrhage expansion. Results: Fifty-four percent of the patients experienced progression in the size of the lesion in the initial 24 hours postinjury. A PIH was independently associated with worsened Glasgow coma scale (GCS) score (2.99, 1.04~8.60), the presence of subarachnoid hemorrhage (6.29, 2.48~16.00), the presence of a subdural hematoma (6.18, 2.13~17.98), the presence of an epidural hematoma (5.73, 1.18~27.76), and the presence of a basal cistern effacement (10.93, 1.19~99.57). Conclusion: For patients undergoing scanning within 2 hours of injury, the rate of PIH approaches 61%. Early repeated CT scanning is indicated in patients with a nonsurgically-treated hemorrhage revealed on the first CT scan. Worsened GCS score, significant hematoma growth and effacement of the basal cisterns on the initial CT scan are powerful predictors of which patients will require surgery. These findings should be important factors in understanding and managing of PIH.

• Journal of Chest Surgery
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• v.17 no.1
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• pp.94-100
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• 1984

The purpose of present study is to investigate the significance of preoperative evaluation with perfusion lung scintigraphy in patients with lung cancer. Lung scans with the use of macroaggregated human serum albumin labeled with technetlum-99m were carried out in 35 patients with lung cancer before thoracotomy at Seoul National University Hospital during the period from November 1981 to September 1983. The relationship between size of the perfusion defect as seen by perfusion lung scan and size of the mass lesion as seen radiologically was correlated with the presence of regional adenopathy and resectability. Among patients with a larger perfusion defect than mass lesion on chest X-ray film.86% were found to have regional lymph node involvement with 29% resectability, whereas among patients in whom a larger defect was not present only 14% had such extension of the disease with 93% resectability. The relative pulmonary arterial perfusion of affected lung was calculated from the counts of radioactivity recorded from affected lung on both anterior and posterior scans expressed as a percentage of the total counts in the scan. The mean relative pulmonary arterial perfusion of the inoperable group [34\ulcorner%] is significantly different from both that of the pneumonectomy group [39\ulcorner%] and that of the lobectomy group [48\ulcorner%].(p<0.01)