• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.813-822
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• 1998

Background: Extubation is recommended to be performed at minimum pressure support (PSmin) during the pressure support ventilation (PSV). In field, physicians sometimes perform additional 1 hr T-piece trial to the patient at PSmin to reduce re-intubation risk. Although it provides confirmation of patient's breathing reserve, weaning could be delayed due to increased airway resistance by endotracheal tube. Methods: To investigate the effect of additional 1 hr T-piece trial on weaning outcome, a prospective study was done in consecutive 44 patients who had received mechanical ventilation more than 3 days. Respiratory mechanics, hemodymic, and gas exchange measurements were done and the level of PSmin was calculated using the equation (PSmin=peak inspiratory flow rate $\times$ total ventilatory system resistance) at the 15cm $H_2O$ of pressure support. At PSmin, the patients were randomized into intervention (additional 1 hr T-piece trial) and control (extubation at PSmin). The measurements were repeated at PSmm, during weaning process (in cases of intervention), and after extubation. The weaning success was defined as spontaneous breathing more than 48hr after extubation. In intervention group, failure to continue weaning process was also considered as weaning failure. Results: Thirty-six patients with 42 times weaning trial were satisfied to the protocol. Mean PSmin level was 7.6 (${\pm}1.9$)cm $H_2O$. There were no differences in total ventilation times (TVT), APACHE III score, nutritional indices, and respiratory mechanics at PSmin between 2 groups. The weaning success rate and re-intubation rate were not different between intervention group (55% and 18% in each) and control group (70% and 20% in each) at first weaning trial. Work of breathing, pressure time product, and tidal volume were aggravated during 1 hr T-piece trial compared to those of PSmin in intervention group ($10.4{\pm}1.25$ and $1.66{\pm}1.08$ J/L in work of breathing) ($191{\pm}232$ and $287{\pm}217$cm $H_2O$ s/m in pressure time product) ($0.33{\pm}0.09$ and $0.29{\pm}0.09$ L in tidal volume) (P<0.05 in each). As in whole, TVT, and tidal volume at PSmin were significantly different between the patients with weaning success ($246{\pm}195$ hr, $0.43{\pm}0.11$ L) and the those with weaning failure ($407{\pm}248$ hr, $0.35{\pm}0.10$L) (P<0.05 in each). Conclusion : There were no advantage to weaning outcome by addition of 1 hr T-piece trial compared to prompt extubation to the patient at PS min.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.1
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• pp.44-51
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• 2009

Proper test methods and instruments for evaluating score or creasing crack have not been provided, although score crack trouble occurs frequently in manufacturing corrugated containers. Because existing creasability tester has the limitation of the available thickness of test piece and folding rate, it cannot be used for corrugated fiberboards with high thickness. In this study, we developed the laboratory test instrument and the method to determine the score or creasing crack of corrugated fiberboard. This instrument can evaluate folding resistance of corrugated board without restriction on the folding rate and thickness of specimen. Corrugated fiberboard had the different folding behavior from linerboard when it was creased. By using this test machine, score crack can be objectively determined by folding test piece to the certain folding angle with constant folding rate.

• Design & Manufacturing
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• v.16 no.1
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• pp.21-26
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• 2022

In the CNC machining process, problems such as lowering of machine operation rate, setting errors, and machining precision occur due to the increase in setting time and preparation time. These machining errors cause delays in delivery and increase in cost due to an increase in the number of mounting and dismounting of the workpiece, an increase in measurement and reprocessing time, and an increase in the finishing time in the assembly process. Therefore, in this study, by automating the setting of the work piece using OMV (On Machine Verification), which is a meteorological measurement system, the preparation time for machining the work piece and the setting accuracy were improved, the rework rate was reduced, and the mold manufacturing process was shortened. Through the advancement, standardzation, and automation of the mold part manufacturing process, we have improved productivity by minimizing low-value-added repetitive tasks. In addition, the measurement time was reduced by more than 50% and the machining measurement rate was improved by more than 20%, eliminating repetitive work for correcting machining defects, and reducing the work preparation time by more than 15% through automatic setting.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1043-1058
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• 1990

The Strain rate effect in electro-magnetic forming, which is one of the high velocity forming methods, is studied by the finite element method in this paper. The forming process is simplified by neglecting the coupling between magnetic field and work-piece deformation, and the impulsive magnetic pressure is regarded as inner pressure load. A rate-dependent elasto-plastic material model, of which tangential modulus depends of effective strain rate, is proposed. The model is shown to well describe the transient increase of yield stresses, the decreases of the final displacement and yield stress, the decrease of the difference in the distribution of deformation along the axial direction, and the change of deformation mechanism due to strain rate effect. As a result, displacement, final deformed shape, radial velocity, deformation energy, and the changes of effective stress, effective strain and effective strain rate through plastic working are given. Based on the results, the effectiveness of this model and the strain rate effect of the deformation process of the work-piece are discussed.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.1
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• pp.73-86
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• 2014

Persimmon juice dye-printed fabrics with printing were used for a Galot one-piece dress. The Galot dress was assessed in comparison to a white undyed one-piece dress of the same design through a wearing test conducted in a climatic chamber with an air temperature of $30{\pm}1^{\circ}C$, $50{\pm}5%$ R.H, and 0.2m/sec air movement on 4 healthy female subjects in their 20s. The subjects went through a 30-min stable period, a 30-min exercise of walking on a $5^{\circ}$ slope treadmill at 70m/min period, and a 20-min recovery period. In addition, a physiological reaction and subjective sensation were estimated. The results showed that significant differences were mostly observed from a sweating period that occurred during the latter half of the exercise. More specific results are as follows. First, skin temperature on the chest and mean skin temperature were significantly higher (p<.01) in rayon dyed sample dresses. Second, micro-humidity on the back showed a significant difference (p<.01). Both cotton and rayon persimmon juice dyed sample dresses produced lower microhumidity than their counterparts and as for cotton the difference occurred over the entire experimental period; however, it occurred after the middle of the exercise period for rayon. Third, the sweating rate on the back decreased in both cotton and rayon with persimmon juice dye but no significant difference was observed. Fourth, subjective three sensations revealed significant differences between cotton and rayon (p<.01), indicating that the subjects felt more cool, dryer and more comfortable in a cotton Galot. As described above, the analysis of physiological responses and the subjective sensation of undyed and dyed clothing shows the effect of persimmon juice dyeing. Persimmon juice dyeing also seemly increased air permeability, moisture regain and permeability facilitating body heat ventilation, as micro-humidity and sweat rate were lowered. However, this was not shown consistently in subjective responses on comfort especially when wearing rayon dresses.

• Journal of KIISE
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• v.44 no.7
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• pp.742-747
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• 2017

In this paper, we propose a novel approach to improve the performance of the Convolutional Neural Network(CNN) word embedding model on top of word2vec with the result of performing like doc2vec in conducting a document classification task. The Word Piece Model(WPM) is empirically proven to outperform other tokenization methods such as the phrase unit, a part-of-speech tagger with substantial experimental evidence (classification rate: 79.5%). Further, we conducted an experiment to classify ten categories of news articles written in Korean by feeding words and document vectors generated by an application of WPM to the baseline and the proposed model. From the results of the experiment, we report the model we proposed showed a higher classification rate (89.88%) than its counterpart model (86.89%), achieving a 22.80% improvement. Throughout this research, it is demonstrated that applying doc2vec in the document classification task yields more effective results because doc2vec generates similar document vector representation for documents belonging to the same category.

• Journal of the Korean Society of Costume
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• v.54 no.1
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• pp.97-108
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• 2004

This study was conducted to examine the marking efficiency of a dress pattern in order to reduce textile loss by pattern marking. A basic one-piece dress pattern saved to the Yuka CAD System was graded with different sizes and arranged for industrial purpose to calculate the marking efficiency in different conditions. Condition of marking experiment is made it a rule to use 150cm textile width and apply 44, 55, 66 pattern size for three pieces of a dress patterns. The results of the study indicated that the marking efficiency rates of the dress pattern with a separate facing was higher than the one with a self facing. In the dress pattern with a separate facing, the separated seam at center back was appeared to have a higher marking efficiency than the extended seam. It was also found that the efficiency rate was higher in the pattern with a seam at center back when comparing with the dress pattern without a seam. When the marking with a horizontally-loaded collar was compared with a vertically-loaded collar, the efficiency rate was higher for the collar loaded horizontally, The result of the study showed that the type of facing, the location of a seam, and the direction of collar loading were the factors directly related to increasing marking efficiency. The dress patterns marked efficiently in terms of a type of facing, seam, and collar treatment can reduce fabric loss and also shorten the time needed for marking process.

• Journal of the Korea Fashion and Costume Design Association
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• v.4 no.1
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• pp.85-98
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• 2002

This study aims to present basic data on current uniforms for the practical improvement and quality betterment of their design by investigating and analysing the uniform designs worn by employees working in department stores, shopping malls and financial firms. For the research, after taking pictures of employees wearing uniforms from various occupations in Daejeon area from April 15 to May 24, 2001, the uniform styles, and the shape, color and pattern of each item were analysed by a group of four costume experts. The result is as follows: First, the uniform forms are classified by the style, and silhouette. It was found that the overall silhouette mostly consisted of hourglass silhouette, and two-piece suits. Second, for the color of each item, black was the most common color for the jacket, skirt, pants and white for the one-piece dress. Third, plain, abstract, and striped patterns, and polka dots were used for the uniforms. Among them the plain pattern accounts for the highest rate.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.3-11
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• 1999

The atomic fuel rods between top and bottom end pieces of reactor need to be extended for high combustion rate of future-type fuel to increase the irradiation in the axial direction. For allowing axial extension of the fuel rods, the space between top and bottom end pieces should be expanded. Thus the thickness reduction of the flow plate is necessary. This study was carried out the mechanical strength test by using strain gages as a function of flow plate thickness, the existence of skirt and loading condition for the Korean Fuel Assembly(KOFA). The experimental apparatus was designed for load conditions, uniformly distributed load and displacement. Test method using whiffle tree of uniformly distributed load has been comparatively conservative. The test results were compared with those of finite element analysis and the test method on bottom end piece was established.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.272-277
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• 1998

Chemical-Mechanical Polishing (CMP) refers to a material removal process done by rubbing a work piece against a polishing pad under load in the presence of chemically active, abrasive containing slurry. CMP process is a combination of chemical dissolution and mechanical action. The mechanical action of CMP involves tribology. The liquid slurry is trapped between the wafer(work piece) and pad(tooling) forming a lubricating film. For the first step to understand material removal rate of the CMP process, the lubricational analyses were done with commercial 100mm diameter silicon wafers to get nominal clearance of the slurry film, roll and pitch angle at the steady state. For this purpose, we calculate slurry pressure, resultant forces and moments at the steady state in the range of typical industrial polishing conditions.