• Bulletin of the Korean Mathematical Society
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• v.43 no.4
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• pp.671-677
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• 2006

Let $A, B{\in}B(H)$ be Hilbert space contractions, and let ${\Delta}_{AB}$ be the elementary operator ${\Delta}_{AB}:X{\rightarrow}AXB-X$. A number of conditions which are equivalent to '${\Delta}_{AB}$ has closed range' are proved.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.6
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• pp.266-272
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• 2014

Purpose: This study was conducted in order to investigate the therapeutic effect of closed reduction according to a classification in patients with nasal bone fracture. Methods: The study was conducted retrospectively on 186 patients with a mean age of 38 years (range: 7 to 80 years). All patients were diagnosed by clinical and radiologic examination, and then classified according to Hwang's classification by computed tomography. The patients were further classified by their age, gender, causes of fracture, operation timing after fracture, concurrent facial bone fracture, and complications. All patients underwent the same reduction and treatment protocol and were then followed up regularly for at least three months. Results: The cause of the fracture was slip down, and the highest prevalence was shown in the 20s. The mean operation timing after fracture was 4.1 days (range: 1 to 14 days), and it tended to be longer in the case of defected septal bone or more severe fracture. The most common concurrent facial bone fracture was orbital blow-out fracture, and zygomaticomaxillary complex and maxillary fracture occured frequently. The largest number of complications occurred in class III and IIBs patients, and the main complication was postoperative pain. Conclusion: Results of nasal bone closed reduction on the 186 patients showed that serious complications rarely occurred. Closed reduction is generally an effective treatment for nasal bone fracture. However, in the case of severe concurrent septal bone fracture or comminuted fracture with depression, open reduction should be considered. Further study with a larger number of patients and further classification is required.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.39-47
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• 1987

The records of 268 patients, who were diagnosed as spontaneous pneumothorax during the period 1975 to 1984, treated at the department of thoracic and cardiovascular surgery, Hanyang University Hospital, were reviewed retrospectively to evaluate the effect of surgical intervention on each indications. Of these,.61 patients [22.8%] were taken operation to treat the pneumothorax after closed thoracostomy. We have classified the 61 patients to evaluate the therapeutic effect on each indications. And the therapeutic effect is based on the chest tube indwelling days. The results were as follows: 1. The chest tube indwelling days of the group who were taken closed thoracostomy only was average 14.13*9.17 days [range 5-66 days], and that of the group who were finally taken the thoracotomy after closed thoracostomy was 21.85*12.30 days [range 5-55 days]. 2. The indications of thoractomy were thoracoscopic findings, recurrence and continuous air leakage. 3. The chest tube indwelling day of the group who was taken thoracotomy by thoracoscopic findings was average 11.67*6.51 day, that was relatively short compared to those of the other groups. 4. The continuous air leakage group after closed thoracostomy was subdivided into three subgroups, continuous air leakage in 1st attack, thoracoscopic findings in 1st attack, and recurrence. 5. Of these, the chest tube indwelling day of the subgroup, who was taken operation by thoracoscopic findings, was 21.33e8.26, that was relatively short compared with those of the other subgroups. We use the thoracoscope as excellent diagnostic tool to detect the operation indication in the spontaneous pneumothorax patients. And we gain the benefits to shorten the chest tube indwelling days and admission days, and also to protect the recurrence.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.3
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• pp.80-86
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• 2000

Eddy covariance method is widely used in measuring vertical fluxes of mass and energy between the atmosphere and the biosphere. In this method, scalar concentration is measured with either open-path or closed-path sensors. For the latter, fluctuations of scalar concentration are attenuated as the sample travels through a long tube, resulting in flux loss. To quantify this tube attenuation, water vapor concentrations measured with both closed-path and open-path sensors were analyzed. Our statistical analysis showed that the power spectral density obtained from the closed-path sensor was different from that from the open-path sensor in the frequency range of > 0.5 Hz. The loss of water vapor flux due to tube attenuation was < 5% during midday. At nighttime, however, the flux loss increased significantly because of the low wind speeds and the weak turbulence sources. Theoretical calculation for the tube attenuation showed a small bias in high frequency range probably because of the interaction of sticky water vapor with a tube wall.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.12
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• pp.1646-1654
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• 2002

A two-phase closed thermosyphon was one of the most effective devices in the removing heat because of its simple structure, thermal diode characteristics, wide operating temperature range and so on. In this study, a two-phase closed thermosyphon(working fluid PFC(C6F14), container copper(inner grooved surface)) was fabricated with a reservoir which can change the fill charge ratio. The experiments were performed in the range of 50~600W heat flow rate and 10~70% fill charge ratio. The results were compared with some correlations that were presented by Rohsenow and Immura et al. in the evaporator, by Nusselt, Gross and Uehara et al. in the condenser and by Cohen and Bayley, Wallis, Kutateladze and Faghri et al. in heat transfer limitation etc.. The heat transfer coefficient at the evaporator increased with the input power. However the effect of the fill charge ratio was nearly negligible. At the condenser, it showed an opposite trend to the evaporator and with increase of the fill charge ratio, showed some enhancement of heat transfer. The heat transport limitation was occurred by the dry-out limitation for small fill charge ratio(10%) and presented about 100W. For the case of large fill charge ratio(Ψ$\geq$40%), it was occurred by the flooding limitation at about 500W.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.5
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• pp.365-372
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• 2021

This paper deals with an optimal Weapon-Target Assignment (WTA) algorithm for Closed-In Weapon Systems (CIWS), considering variable burst time. In this study, the WTA problem for CIWS is formulated based on Mixed Integer Linear Programming (MILP). Unlike the previous study assuming that the burst time is fixed regardless of the engagement range, the proposed method utilizes the variable burst time based on the kill probability according to the engagement range. Thus, the proposed method can reflect a more realistic engagement situation and reduce the reaction time of CIWS against targets, compared to the existing method. In this paper, we first reformulate the existing MILP-based WTA problem to accommodate the variable burst Time. The proposed method is then validated through numerical simulations with the help of a commercial optimization tool.

• Archives of Plastic Surgery
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• v.45 no.4
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• pp.351-356
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• 2018

Background Mallet fracture can easily occur during sports activities or in daily life; however, the principles and methods of treatment for such fractures remain debated. Among the surgical treatments, various methods of closed reduction have been proposed. We treated patients with the extension block method (EBM) and the direct pinning method (DPM), and then compared the results. We assessed differences in range of motion and measurements of finger movement after surgery. Methods A total of 41 patients who underwent surgery from August 2013 to September 2015 were evaluated retrospectively. Among them, 21 patients were treated with the EBM and 20 patients were treated with the DPM. We then compared extensor lag, range of motion, and outcomes according to Crawford's criteria between before surgery and at 6 to 8 months postoperatively. Results The postoperative extensor lag improvement was $4.28^{\circ}$ and $10.73^{\circ}$, and the postoperative arc of motion was $55.76^{\circ}$ and $61.17^{\circ}$ in the EBM and DPM groups, respectively. The Crawford assessment showed no statistically significant difference between the groups, although the score in the DPM group was higher than that in the EBM group (3.5 vs. 3.1). Conclusions As closed reduction methods for the treatment of mallet fracture, both the EBM and DPM showed good results. However, the DPM proved to be superior to the EBM in that it produced greater improvements in extensor lag and range of motion.

• Speech Sciences
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• v.12 no.1
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• pp.107-119
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• 2005

The current study considers that the distinctive acoustic properties and variations in the closed plateau are realized by four different pitch accents(/Hi*_ H*/ or /Hi*_$h*_f$ for an emphatic phrase and /hi*_ H*/ for a neutral phrase) in an intermediate phrase in the French intonational structure. Thus, an attempt is made to define the acoustic property of the CP in the ip according to the duration time and pitch range, while different combinations of the four pitch accents of the CP are used to explain the way a speaker will highlight. The duration time of the CP was measured at about 0.67 sec. for males and 0.75 sec. for females. The duration properties of the plateau in the CP were found to control the pitch range based on two different prominent pitch accents, which appeared in more than two APs. Therefore, the ip was identified as having a hierarchical level in the French intonational structure, along with the AP and IP. In addition, the CP in the ip was used as a specific location to explain the pragmatic meaning of the rhythm using the two acoustic factors and different combinations of the four pitch accents.

• Journal of Korean Neurosurgical Society
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• v.54 no.2
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• pp.112-117
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• 2013

Objective : We performed this study to investigate whether the use of closed-suction drainage following microvascular decompression (MVD) causes cerebrospinal fluid (CSF) leakage. Methods : Between 2004 and 2011, a total of 157 patients with neurovascular compression were treated with MVD. MVD was performed for hemifacial spasm in 150 (95.5%) cases and for trigeminal neuralgia in 7 (4.5%) cases. The mean age of the patients was $49.8{\pm}9.6$ years (range, 20-69). Dural substitutes were used in 44 (28.0%) patients. Ninety-two patients (58.6%) were underwent a 4-5 cm craniotomy using drainage (drainage group), and 65 (41.4%) did a small 2-2.5 cm retromastoid craniectomy without closed-suction drainage (no-drainage group). Results : Eleven (7.0%) patients experienced CSF leakage following MVD based on the criteria of this study; all of these patients were in the drainage group. In the unadjusted analyses, the incidence of CSF leakage was significantly related with the use of closed-suction drainage following MVD (12.0% in the drainage group vs. 0% in the no-drainage group, respectively; p=0.003; Fisher's exact test). Those who received dural substitutes and the elderly (cut-off value=60 years) exhibited a tendency to develop CSF leakage (p=0.075 and p=0.090, respectively; Fisher's exact test). In the multivariate analysis, only the use of closed-suction drainage was significantly and independently associated with the development of CSF leakage following MVD (odds ratio=9.900; 95% confidence interval, 1.418 to infinity; p=0.017). Conclusion : The use of closed-suction drainage following MVD appears to be related to the development of CSF leakage.

• Journal of the Korean Society of Safety
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• v.30 no.4
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• pp.86-91
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• 2015

The flash point is used to categorize inflammable liquids according to their relative flammability. Such a categorization is important for the safe handling, storage, and transportation of inflammable liquids. The flash point temperature of two binary liquid mixtures(n-octane+n-decane and n-octane+n-dodecane) has been measured for the entire concentration range using Seta-flash closed cup tester based on the ASTM D3278 method. The closed cup flash point temperature was estimated using the UNIFAC(Universal Functional Activity Coefficient) group contribution model. The experimentally derived flash point was also compared with the predicted flash point from the UNIFAC model. The UNIFAC model is able to estimate the flash point fairly well for n-octane+n-decane mixture and n-octane+n-dodecane mixture.