• Journal of Korean Neurosurgical Society
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• v.29 no.6
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• pp.754-762
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• 2000

Objectives : The surgical results of 80 patients with growth hormone(GH)-producing pituitary adenoma were analyzed retrospectively to evaluate the clinical manifestations and to determine which preoperative factors significantly influenced the surgical outcome. Patients and Methods : The patients consisted of 39 men and 41 women and the age of patients at the time of initial operation ranged from 17 to 67 years(mean age, 40.5 years) Between January 1990 and June 1996, 77 patients underwent transsphenoidal surgery and 3 patients underwent craniotomy for GH-producing pituitary adenoma at our institution. Preoperative administration of octreotide was performed in 18 patients. Surgical control was defined as a postoperative serum basal level of GH less than 5ng/ml. A logistic regression model was used for univariate and multivariate analysis. Probability value of less than 0.05 was considered as statistically significant. Results : The most common presenting symptom was acromegaly, followed by headache, visual disturbance, and fatigability. Visual symptoms were present in 39% of the patients. Diabetes mellitus was associated in 24 patients and hypertension in 12. Preoperative mean basal level of GH was 93.2ng/ml(range 72-500ng/ml) which was closely related with tumor size(p<0.05). Grade II by Hardy's classification was the most common radiological type. Preoperative octreotide treatment significantly reduced the level of GH(p<0.05), but not enough to induce endocrinological remission. One patient died of cerebral infarction after craniotomy. The most common surgical complication was transient diabetes insipidus. The symptom of the earliest improvement after surgery was paresthesia and tightness of the hand and foot, followed by headache and easy fatigability. The preoperative visual symptom was improved in all patients. The patients who had hypertension or DM experienced alleviated symptoms in 67% and 92%, respectively. The overall rate of endocrinological remission was 44%. By multivariate logistic regression analysis, the size of tumor, extrasellar extension, and extent of removal were significant prognostic factors for endocrinologial remission. Conclusion : Early detection of a small tumor without extrasellar extension followed by a complete resection is highly recommended in order to achieve endocrinological cure of GH-producing pituitary adenomas.

• Restorative Dentistry and Endodontics
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• v.33 no.2
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• pp.141-147
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• 2008

This study was aimed to develop an instrument for real-time measurement of fluid conductance and to investigate the hydrodynamics of dentinal fluid. The instrument consisted of three parts; (1) a glass capillary and a photo sensor for detection of fluid movement, (2) a servo-motor, a lead screw and a ball nut for tracking of fluid movement, (3) a rotary encoder and software for data processing. To observe the blocking effect of dentinal fluid movement, oxalate gel and self-etch adhesive agent were used. BisBlock (Bisco) and Clearfil SE Bond (Kuraray) were applied to the occlusal dentin surface of extracted human teeth. Using this new device, the fluid movement was measured and compared between before and after each agent was applied. The instrument was able to measure dentinal fluid movement with a high resolution (0.196 nL) and the flow occurred with a rate of 0.84 to 15.2 nL/s before treatment. After BisBlock or Clearfil SE Bond was used, the fluid movement was decreased by 39.8 to 89.6%.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.12-21
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• 2012

IEEE 802.11 MAC protocol standard, DCF(CSMA/CA), is originally designed to ensure the fair channel access between mobile nodes sharing the local wireless channel. It has been, however, revealed that some misbehavior nodes transmit more data than other nodes through artificial means in hot spot area spreaded rapidly. The misbehavior nodes may modify the internal process of their MAC protocol or interrupt the MAC procedure of normal nodes to achieve more data transmission. This problem has been referred to as a selfish node problem and almost literatures has proposed methods of analyzing the MAC procedures of all mobile nodes to detect the selfish nodes. However, these kinds of protocol analysis methods is not effective at detecting all kinds of selfish nodes enough. This paper address this problem of detecting selfish node using Tsallis-Entropy which is a kind of statistical method. Tsallis-Entropy is a criteria which can show how much is the density or deviation of a probability distribution. The proposed algorithm which operates at a AP node of wireless LAN extracts the probability distribution of data interval time for each node, then compares the one with a threshold value to detect the selfish nodes. To evaluate the performance of proposed algorithm, simulation experiments are performed in various wireless LAN environments (congestion level, how selfish node behaviors, threshold level) using ns2. The simulation results show that the proposed algorithm achieves higher successful detection rate.

• Journal of Gastric Cancer
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• v.1 no.3
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• pp.180-186
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• 2001

Purpose: The prognosis for early gastric cancer (EGC) is favorable, and the 10-year disease-specific survival rate is reported to be around $90\%$. The absolute number of recurred EGC is too small to assess the risk factors, so recruitment of a large number of cases for statistical analysis is very difficult. We carried out this study to analyze the incidence and the patterns of recurrence of EGC and to identify the clinicopathological risk factors for recurrence of EGC. Materials and Methods: The authors retrospectively investigated the follow-up records of 1418 patients who underwent a curative resection for EGC from Jan. 1984 to Dec. 1999 at the Korea Cancer Center Hospital and analyzed them with special reference to cancer recurrence. Results: In this retrospective study of 1418 cases, 43 patients died of a recurrence of gastric cancer, and 105 patients died of unrelated causes. The five-year and the ten-year overall survival rates were $89.6\%$ and $81.7\%$, respectively, while the five-year and the ten-year diseasespecific survival rates were $96.5\%$ and $94.3\%$, respectively. The recurrence patterns of the 45 recurred EGC were hematogenous metastasis (19 cases), lymph node (L/N) metastasis (8 cases), locoregional recurrence (2 cases), peritoneal seeding (3 cases), and combined form (13 cases). The mean time interval to recurrence was 38.6 months, and the number of delayed recurred cases after 5 years was 10 ($22.2\%$). Of the clinicopathologic factors, depth of invasion, L/N metastasis, macroscopic type, lymphatic invasion, and vessel invasion, were significant risk factors in the univariate analysis. However, in the multivariate analysis, only L/N metastasis was an independent prognostic factor. Conclusion: Based on the results of this study, L/N metastasis is an independent prognostic factor. Thus, in patients with node-positive disease, adjuvant therapy might be considered, and long-term close follow-up might facilitate early detection and treatment of recurrent disease due to delayed recurrence.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.69-76
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• 2007

The accumulation curves of phenol in the flesh of apples were measured at $5^{\circ}C$, $25^{\circ}C$ and $40^{\circ}C$ when they were exposed to phenol vapor, The effective diffusivities of phenol at the rind and flesh were determined by comparing its experimentally obtained accumulation curves with simulated ones. The simulation was carried out by the non-steady state diffusion rate equation. The diffusion model assumed the consecutive diffusion of phenol at the rind and flesh of apples. The detection time of phenol in the flesh of apples was shortened with increasing temperature, and it accumulated amount also increased rapidly. The estimated effective diffusivity of phenol at the rind of apples increased with temperature as like $1.1{\times}10^{-13}\;m^2/s$ at $5^{\circ}C$, $1.4{\times}10^{-13}\;m^2/s$ at $25^{\circ}C$ and $2.2{\times}10^{-13}\;m^2/s$ at $40^{\circ}C$, but those at the flesh of apples were invariant as $1.5{\times}10^{-10}\;m^2/s$ at this temperature range. The effect of temperature on the diffusivity of phenol was small, but the increase of the vapor pressure of phenol with temperature accelerated the penetration of phenol at the rind, resulting in the rapid accumulation at the flesh of apple.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.6
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• pp.22-32
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• 2010

Increasingly advanced Information Technology (IT) has changed the operator so as to create more diversified and advanced traffic information demand. To deal with the changing demand in private sector, a concept of on-demand traffic information has been rapidly introduced. However VMS, a product of the first generation of ITS, which was designed to provide the unspecified individuals during driving the car with the basic level of traffic information by the public failed to actively change itself in such a changing pattern. This study was intended to describe the VMS system (tentatively, FM-VMS) which was further developed to accommodate the needs favoring the sophisticated PDA with the public role of providing the unspecified individuals with the equal information. FM-VMS introduced in this study is the device designed to transmit the voice and message to the drivers through the radio information device mounted on a car. A core technology is, unlike FM-DARC and RDS, the Water Making technology which directly inserts the digital signal into FM frequency in use. It's been currently used for broadcasting and security purpose. A detection rate as a result of testing FM-VMS system using Water Making technology was 90% or more in voice and message within 20m from test VMS. When a public-developed VMS information could be transmitted using FM frequency to the relatively vulnerable users (vulnerable to traffic information) in voice on a real-time basis to provide the regional traffic information, and furthermore, VMS message could be received through radio liquid using FM frequency only, it would obviously bring about the innovation in ITS as well as pave the way for creating the new added value down the road.

• Journal of Radiation Protection and Research
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• v.45 no.3
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• pp.117-129
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• 2020

Background: Radiation portal monitors (RPMs) involving plastic scintillators installed at the border inspection sites can detect illicit trafficking of radioactive sources in cargo containers within seconds. However, RPMs may generate false alarms because of the naturally occurring radioactive materials. To manage these false alarms, we previously suggested an energy-weighted algorithm that emphasizes the Compton-edge area as an outstanding peak. This study intends to evaluate the identification of radioactive sources using an improved energy-weighted algorithm. Materials and Methods: The algorithm was modified by increasing the energy weighting factor, and different peak combinations of the energy-weighted spectra were tested for source identification. A commercialized RPM system was used to measure the energy-weighted spectra. The RPM comprised two large plastic scintillators with dimensions of 174 × 29 × 7 ㎤ facing each other at a distance of 4.6 m. In addition, the in-house-fabricated signal processing boards were connected to collect the signal converted into a spectrum. Further, the spectra from eight radioactive sources, including special nuclear materials (SNMs), which were set in motion using a linear motion system (LMS) and a cargo truck, were estimated to identify the source identification rate. Results and Discussion: Each energy-weighted spectrum exhibited a specific peak location, although high statistical fluctuation errors could be observed in the spectrum with the increasing source speed. In particular, ¹³⁷Cs and ⁶⁰Co in motion were identified completely (100%) at speeds of 5 and 10 km/hr. Further, SNMs, which trigger the RPM alarm, were identified approximately 80% of the time at both the aforementioned speeds. Conclusion: Using the modified energy-weighted algorithm, several characteristics of the energy weighted spectra could be observed when the used sources were in motion and when the geometric efficiency was low. In particular, the discrimination between ⁶⁰Co and ⁴⁰K, which triggers false alarms at the primary inspection sites, can be improved using the proposed algorithm.

• Investigative Magnetic Resonance Imaging
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• v.16 no.2
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• pp.152-158
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• 2012

Purpose : To compare the arterial and venous detection sites of triggering methods in contrast-enhanced-MR-venography (CE-MRV) for the evaluation of intracranial venous system. Materials and Methods: 41 healthy patients underwent CE-MRV with autotriggering at either the cavernous segment of internal carotid artery with an inserted time-delay of 6 seconds (n = 20) or the superior sagittal sinus without any timedelay (n = 21). 0.1 mmol/kg gadolinium-based contrast material ($Magnevist^{(R)}$, Schering, Germany) was intravenously injected by hand injection. A sagittal fast-spoiled-gradient-echo-sequence ranging from one ear to the other was performed (TR/TE5.2/1.5, Matrix $310{\times}310$, 124 sections in the 15-cm-thick volume). 17 predefined venous structures were evaluated on all venograms by two neuroradiologists and defined as completely visible, partially visible, or none visible. Results: The rate of completely visible structures were 272 out of 323 (84%) in the arterial triggering CE-MRV and 310 out of 340 (91%) in the venous triggering CE-MRV. The venous triggering CE-MRV demonstrated an overall superior visualization of the cerebral veins than the arterial triggering CE-MRV (Fisher exact test, p < 0.006). Conclusion: CE-MRV using venous autotriggering method provides higher-quality images of the intracranial venous structures compared to that of arterial.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.8
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• pp.1785-1796
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• 2015

In this paper, we investigate achieving the full diversity order and power gains in case of using OSTBCs and quasi-OSBCs in the x channel system with interference alignment with more than 2 antennas at each terminal. A slight degradation is remarked in the case of quasi-OSTBCs. In terms of receiver structure, we show that due to the favorable structure of the channel matrices, the simple zero-forcing receiver achieves the full diversity order, while the interference cancellation receiver leads to degradations in performance. As compared to the conventional scheme, simulation results demonstrate that our proposed schemes achieve 14dB and 16.5dB of gain at a target bit error rate (BER) of 10^-4 in the case of OSTBCs with 3 and 4 antennas at each terminal, respectively, while achieving the same spectral efficiency. Also, a gain of 10dB is achieved at the same target BER in the case of quasi-OSTBC with 4 antennas at each terminal.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.4
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• pp.460-466
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• 2004

This study was undertaken with the aim to establish a reliable radioimmunoassay (RIA) system for urinary pregnanediol glucuronide (PdG) and to employ it for monitoring the reproductive status of dairy cows. Urine and blood samples were collected from the Holstein cows both pregnant and non-pregnant. The samples were then investigated for evaluating the relationship between progesterone ($P_{4}$) in blood and PdG in urine adjusted with or without urinary creatinine basis. Biweekly urine collection was employed for three cows in estrous and those artificially inseminated, while urine from pregnant cows was collected on a monthly basis. P_{4}$ and PdG levels were measured by enzymeimmunoassay (EIA) and RIA techniques, respectively. Our results indicated the sensitivity of PdG for RIA being 35 pg/tube and the recovery rate of 100%. Urinary creatinine concentrations also fluctuated within a day, but change at midday was not noteworthy. Regardless of the time of urination the change in concentrations of PdG was relatively smaller and did not vary significantly. The urinary PdG concentration showed periodic changes as that with serum P_{4}$ levels during the cow's estrus cycle. The correlation coefficient rose when creatinine level in urine was adjusted but the change was also not significant. The concentrations of PdG during the luteal phase were detected between 8.2 and 17.4 ng/ml, three to five times higher than that in the follicular phase. The concentration of PdG from pregnant cows (21 days after conception) was three to four times higher than in the nonpregnant cows. Our finding suggests that the determination of urinary PdG could be reliably employed for early pregnancy detection. The urinary PdG level continued to raise until 30 days pre-partum while the concentration reached its peak at 30 ng/ml, after which it started to fall 18 to 30 days before parturition and finally fell to its nadir value one week after parturition. As the correlation coefficient between the urinary PdG and serum P_{4}$ was higher than that corrected by urinary creatinine it can be suggested that the adjustment is not needed. The concentrations of urinary PdG could be maintained stably for 2 days in urine samples stored at room temperature and extended to 8 days when the samples were pretreated by boiling for 30 minutes. In conclusion urinary PdG concentration even without the need for creatinine basis adjustment can be used directly for monitoring the reproductive status of dairy cows.