• Journal of Korean Neurosurgical Society
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• v.49 no.1
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• pp.20-25
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• 2011

Objective: Due to longer life spans, patients newly diagnosed with unruptured intracranial aneurysms (UIAs) are increasing in number. This study aimed to evaluate how management of UIAs in patients age 65 years and older affects the clinical outcomes and post-procedural morbidity rates in these patients. Methods: We retrospectively reviewed 109 patients harboring 136 aneurysms across 12 years, between 1997 and 2009, at our institute. We obtained the following data from all patients: age, sex, location and size of the aneurysm(s), presence of symptoms, risk factors for stroke, treatment modality, and postoperative 1-year morbidity and mortality. We classified these patients into three groups: Group A (surgical clipping), Group B (coil embolization), and Group C (observation only). Results: Among the 109 patients, 56 (51.4%) underwent clipping treatment, 25 (23%) patients were treated with coiling, and 28 observation only. The overall morbidity and mortality rates were 2.46% and 0%, respectively. The morbidity rate was 1.78% for Clipping and 4% for coiling. Factors such as hypertension, diabetes mellitus, hypercholesterolemia, smoking, and family history of stroke were correlated with unfavorable outcomes. Two in the observation group refused follow-up and died of intracranial ruptured aneurysms. The observation group had a 7% mortality rate. Conclusion: Our results show acceptable favorable outcome of treatment-related morbidity comparing with the natural history of unruptured cerebral aneurysm. Surgical clipping did not lead to inferior outcomes in our study, although coil embolization is generally more popular for treating elderly patients, In the treatment of patients more than 65 years old, age is not the limiting factor.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.487-492
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• 2010

For developing a two-stroke free-piston hydrogen engine with high efficiency and low emission, determination of the scavenging type is one of the most important factor. In this research, backfire characteristics for loop scavenging were analyzed with the number of piston crevice volume and piston expansion speed. Rapid Compression Expansion Machine, RCEM was used for combustion research of the free piston $H_2$ engine in the experiment. As the results, it was shown that although backfire occurring in a loop scavenging type can be partially controled by a complete exhaust of burned gas, possibility of backfire basically exist due to the structure which piston crevice volumes contact with fresh mixture in a scavenging port. However, a loop scavenging may be considered as combustion chamber of a free piston $H_2$ engine from the point of view that backfire does not occur nearby lean equivalence ratio obtained high thermal efficiency. It was also analyzed that an advances of backfire occurrence timing with increase of the fuel-air equivalence ratio were due to promotion of flame propagation into piston crevice volumes by decrease of the quenching distance.

• Journal of Korean Neurosurgical Society
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• v.39 no.3
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• pp.210-214
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• 2006

Objective : We investigate risk factors of cerebral microbleeds[MBs] and their relation to concomitant magnetic resonance[MR] findings in intracerebral hemorrhages[ICHs] patients. Methods : We studied 100 consecutive patients with primary ICH over a 1-year period. These patients underwent brain MR images using 3.0-T scanners within the first week of the hemorrhage. MBs and old hematomas were located and counted by using $T2^*-weighted$ gradient-echo MR imaging. We also counted lacunes and graded white matter and periventricular hyperintensity on T1- and T2-weighted spin-echo sequences. The association between MBs and vascular risk factors and MR abnormalities were analyzed. Results : MBs were seen in 77 of ICH patients, and their number ranged from 1 to 65 lesions [mean 11, median 6]. The locations of MBs were subcortex-cortex [40.6%], basal ganglia [26.7%], thalamus [14.1 %], brain stem [12.5%], and cerebellum [9.1 %]. Analysis of clinical data revealed that age, hypertension, history of stroke, and duration of hypertension were frequently associated with MBs. The incidence of lacunes, old hematomas, and advanced leukoaraiosis was significantly higher in the MBs group, compared with the patients without MBs. Conclusion : MBs are frequently observed in ICH patients with advancing age, chronic hypertension, and previous hemorrhagic stroke, and are also closely related with morphological signs of occlusive type microangiopathy, such as lacunar infarct and severe leukoaraiosis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1345-1352
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• 2010

The structural approach in the signature verification, representing a signature as a structural form of local primitives, shows an excellent performance since it counts in the local characteristics such as local variation, stroke complexity, and etc. However, this method has a problem of template data sizing which can not fix the number of subpatterns comprising a signature. In this paper, we proposed a new algorithm to reduce the signature data into a fixed size by selecting a fixed number of subpatterns which is considered as important parts. As a result, it shows more excellent performance when the fixed sized sub-patterns is applied with local weights extracted from variational characteristics and complexities in local part. And the number of subpatterns representing a signature reference model can be fixed under a certain number of segments determined appropriately.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.3
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• pp.56-64
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• 2000

A friction force measurement system using the floating liner method was developed to study the frictional behavior of piston rings. The measurement system was carefully designed to control the effect of the piston secondary motion and the temperature of cylinder wall and oil. The friction force between the barrel shaped piston ring and the cylinder liner, was measured under the condition of flooded oil supply. The measured friction forces were classified into five frictional modes with regard to the combination of predominant lubrication regimes(boundary, mixed and hydrodynamic lubrication) and stroke regions(midstroke and dead centers). The modes could be identified on the Stribeck diagram of the friction coefficients and the dimensionless number of ㎼/p, where the friction coefficients are evaluated at near the midstroke and dead centers.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.3
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• pp.52-58
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• 1999

This paper proposed and algorithm for distinguishing Korean and English characters which can be applied to multi-size and multi-font images The proposed algorithm distinguishes them as the ratio height to width of each character, the number of connected component, existing or not of stroke image on the left-upper area and detection of bars in an input image. The process of detecting bar is a sequence of left, upper, right, and lower. The proposed method was experimented and proved good performance for the Myungjo font, the Sinmyungjo font, the Gothic font, and the Kungseo font of Hanguel word processor which is widely used for the writing of documents.

• Journal of Power System Engineering
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• v.10 no.4
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• pp.159-164
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• 2006

In recent, the marine engine of a large size is being realized a lower speed, longer stroke and a small number of cylinders for the energy saving. Consequently the variation of rotational torque became larger than former days because of the longer delay-time in fuel oil injection process and an increased output per cylinder. It was necessary that algorithms have enough robustness to suppress the variation of the delay-time and the parameter perturbation. This paper shows the structure of hybrid F-NFC against the delay-time and the perturbation of engine parameter as modeling uncertainties, and the design of the robust speed controller by hybrid F-NFC for the engine. And, The Parameter values of linear equation are determined by RC-GA for F-NFS. The hybrid F-NFC is combined the F-NFC and PID controller for filling up each.

• Journal of Sasang Constitutional Medicine
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• v.3 no.1
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• pp.173-183
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• 1991

These studies were conducted about the effects of Ferric oxide in the aspect of the basic pharmacology through experimental animals with the investigation of its clinical effects on oriental medical literatures of Ferric oxide. The results were as follows: 1. The analgenic effects induced by acetic acid were significant. 2. The anticonvulsive effects induced by ECT unit were significant. 3. The sedative effects in Rotor rod method were significant. 4. The number of platelets was increased but not significantly. 5. Prothrombin time was decreased significantly. 6. Fibrinogen was increased but not significantly. 7. The degree of concentration of FDP was decreased significantly. According to the above results, it is considered that Ferric oxide retains effectiveness on the treatment of cerebral stroke.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.4
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• pp.357-363
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• 2013

Most serious patients who have the paralysis of their ankles can't use of their feet freely. But their ankles can be recovered by an ankle bending rehabilitation exercise and a ankle rotating rehabilitation exercise. Recently, the professional rehabilitation therapeutists are much less than stroke patients in number. Therefore, the ankle-rehabilitation robot should be developed. The developed robot can be dangerous because it can't measure the applied bending force and twisting moment of the patients' ankles. In this paper, the six-axis force/moment sensor for the ankle-rehabilitation robot was specially designed the weight of foot and the applied force to foot in rehabilitation exercise. As a test results, the interference error of the six-axis force/moment sensor was less than 2.51%. It is thought that the sensor can be used to measure the bending force and twisting moment of the patients' ankles in rehabilitation exercise.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.116-123
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• 2005

An experimental investigation on the static and dynamic stall characteristics of elliptic airfoil was performed by PIV velocity field measurements. The flow Reynolds number was $3.13{\times}10^5$ and the reduced frequency of the pitch oscillation ranged from 0.075 to 0.125. The onset of static stall was caused by boundary layer separation which started at the trailing edge and progressed toward the leading edge. However, dynamic stall was caused by the vortex shed at the leading edge region and the flow field showed a vortex dominated flow with turbulent separation and alternate vortex shedding. The increase of reduced frequency increased the dynamic stall angle of attack and intensified the flow hysteresis in the down-stroke phase.