• Journal of Korean Foot and Ankle Society
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• v.21 no.4
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• pp.144-150
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• 2017

Purpose: To assess the clinical and radiographic results and complications of arthroscopy-assisted reduction and percutaneous fixation for patients with tongue-type Sanders type II calcaneal fractures. Materials and Methods: Between August 2014 and December 2015, 10 patients who underwent surgery using subtalar arthroscopic assisted reduction and percutaneous fixation for tongue-type Sanders type II calcaneal fractures were reviewed. The mean age was 50.8 years (36~62 years), and the mean follow-up period was 24 months (12~40 months). The clinical results were evaluated using the visual analogue scale (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score at the regular follow-ups, and the foot function index (FFI) at the last follow-up. The subtalar range of motion (ROM) was evaluated and compared with the uninjured limb at the last follow-up. The radiographic results were assessed using the Bohler's angle from the plain radiographs and the reduction of the posterior calcaneal facet using computed tomography (CT). The postoperative complications were assessed by a chart review. Results: The VAS and AOFAS ankle-hindfoot score improved until 12 months after surgery. The FFI was 15 (1.8~25.9) and subtalar ROM was 75.5% (60%~100%) compared to the uninjured limb at the last follow-up. The $B{\ddot{o}}hler^{\prime}s$ angle was increased significantly from $2^{\circ}$ ($-14^{\circ}{\sim}18^{\circ}$) preoperatively to $21.8^{\circ}$ ($20^{\circ}{\sim}28^{\circ}$) at the last follow-up. The reduction of the posterior facet was graded as excellent in five feet (50.0%) and good in five (50.0%) on CT obtained at 12 months after surgery. One foot (10.0%) had subfibular pain due to a prominent screw head. One foot (10.0%) had pain due to a longitudinal tear of the peroneal tendon that occurred during screw insertion. Conclusion: Subtalar arthroscopic-assisted reduction of the posterior calcaneal facet of the subtalar joint and percutaneous fixation is a useful surgical method for tongue-type Sanders type II calcaneal fractures.

• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.175-182
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• 1998

Any classification process using SAR images presupposes the reduction of multiplicative speckle noise, since the variations caused by speckle make it extremely difficult to distinguish between neighboring classes within the feature space. Therefore, several adaptive filter algorithms have been developed in order to distinguish between them. These algorithms aim at the preservation of edges and single scattering peaks, and smooths homogeneous areas as much as possible. This task is rendered more difficult by the multiplicative nature of the speckle noise the signal variation depends on the signal itself. In this paper, LEE(Lee 1908) and R-LEE(Lee 1981) filters using local statistics, local mean and variance, are applied to RADARSAT SAR images. Also, a new method of speckle filtering, EPOS(Edge Preserving Optimal Speckle)(Hagg & Sties 1994) filter based on the statistical properties of speckle noise is described and applied. And then, the results of filtering SAR images with LEE, R-LEE and EPOS filters are compared with mean and median filters.

• Journal of Mechanical Science and Technology
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• v.18 no.3
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• pp.499-512
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• 2004

The effects of swirl intensity on non-reacting and reacting flow characteristics in a flat flame burner (FFB) with four types of swirlers were investigated. Experiments using the PIV method were conducted for several flow conditions with four swirl numbers of 0, 0.26, 0.6 and 1.24 in non-reacting flow. The results show that the strong swirling flow causes a recirculation, which has the toroidal structures, and spreads above the burner exit plane. Reacting flow characteristics such as temperature and the NO concentrations were also investigated in comparison with non-reacting flow characteristics. The mean flame temperature was measured as the function of radial distance, and the results show that the strong swirl intensity causes the mean temperature distributions to be uniform. However the mean temperature distributions at the swirl number of 0 show the typical distribution of long flames. NO concentration measurements show that the central toroidal recirculation zone caused by the strong swirl intensity results in much greater reduction in NO emissions, compared to the non-swirl condition. For classification into the flame structure interiorly, the turbulence Reynolds number and the Damkohler number have been examined at each condition. The interrelation between reacting and non-reacting flows shows that flame structures with swirl intensity belong to a wrinkled laminar-flame regime.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.97-104
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• 2000

Evaluating a Review-Level Ground Motion is a key to efficiently perform Seismic Margin Assessment of nuclear power plants whose purpose is to determine a ground motion level for which a plant has high-confidence-of-a-low-probability of seismic-induced core damage and to identify any weaker-link components. In this study a method to obtain RLGMs is reviewed which is recommended by Electric Power Research Institute and implemented to be applied to Limerick site in eastern and central U. S as a case study. This method provides reasonable and site-specific RLGMs as minimum required plant HCLPF for SMA that meet a target mean seismic core-damage frequency based on seismic hazard results and generic values of uncertainty and randomness parameters of the core-damage fragility curves. In addition high-frequency RLGM is justifiably modified to reflect the increased seismic capacity of high-frequency components and spatial variation and incoherence of input ground motion on a basemat of large structures by establishing a method to obtain high0-frequency reduction factors according to EPRI guidelines.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.581-586
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• 2008

This study aims to examine the existing single rating index in terms of level reduction limit of heavy-weight floor impact sound. To achieve this goal, sounds which have same loudness according to rating methods were suggested to subjects. And followings are results. 1) The rating method of measurement frequency level average is more suitable than that of other methods which are dependent on specific frequency for rating heavy-weight floor impact sound. 2) Level average for measurement frequency of 31.5Hz - 500Hz is more correspondent to psycho-acoustic response than that of measurement frequency of 63Hz - 500Hz which is for KS F 2863-2, existing rating method.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.533-536
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• 2003

In this paper we propose AODC(Adaptive Over Driving Circuit) to reduce motion blurring and compensate color accuracy on LCD monitor. The proposed method has been experimented on adaptive ODC by motion grade after detection of moving objects. Also, we discriminated motion grade by mean value's degree of differential value between current frame and previous frame to detect moving objects. It has been found that the proposed method provides better performance than the conventional one from the point of view on the blurring of movement objects through the experiment. Its results show that the proposed method is very suitable for a motion blurring reduction on LCD monitor.

• Proceedings of the KSPS conference
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• 2005.04a
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• pp.91-94
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• 2005

The performance of speech recognition is degraded by the mismatch between training and test environments. Many methods have been presented to compensate for additive noise and channel effect in the cepstral domain, and Cepstral Mean Subtraction (CMS) is the representative method among them. Recently, high order cepstral moment normalization method has introduced to improve recognition accuracy. In this paper, we apply high order moment normalization method and smoothing filter for real-time processing. In experiments using Aurora2 DB, we obtained error rate reduction of 49.7% with the proposed algorithm in comparison with baseline system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.3
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• pp.282-287
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• 2009

This study aims to examine the existing single rating index in terms of level reduction limit of heavy-weight floor impact sound. To achieve this goal, sounds which have same loudness according to rating methods were suggested to subjects. And followings are results. 1) The rating method of measurement frequency level average is more suitable than that of other methods which are dependent on specific frequency for rating heavy-weight floor impact sound. 2) Level average for measurement frequency of $31.5\;Hz{\sim}500\;Hz$ is more correspondent to psycho-acoustic response than that of measurement frequency of $63\;Hz{\sim}500\;Hz$ which is for KS F 2863-2, existing rating method.

• Wind and Structures
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• v.17 no.5
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• pp.553-564
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• 2013

By using the nonlinear aerostatic stability theory together with the method of mean wind decomposition, a method for nonlinear aerostatic stability analysis is proposed for long-span suspension bridges under yaw wind. A corresponding program is developed considering static wind load nonlinearity and structural nonlinearity. Taking a suspension bridge with three towers and double main spans as an example, the full range aerostatic instability is analyzed under wind at different attack angles and yaw angles. The results indicate that the lowest critical wind speed of aerostatic instability is gained when the initial yaw angle is greater than $0^{\circ}$, which suggests that perhaps yaw wind poses a disadvantage to the aerostatic stability of a long span suspension bridge. The results also show that the main span in upstream goes into instability first, and the reason for this phenomenon is discussed.

• The Journal of the Acoustical Society of Korea
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• v.18 no.1
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• pp.38-44
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• 1999

In this paper, a new spectral subtraction technique with two microphone inputs is proposed. In conventional spectral subtraction using a single microphone, the averaged noise spectrum is subtracted from the observed short-time input spectrum. This results in reduction of mean value of noise spectrum only, the component varying around the mean value remaining intact. In the method proposed in this paper, the short-time noise spectrum excluding the speech component is estimated by introducing the blocking matrix used in Griffiths-Jim-type adaptive beamformer with two microphone inputs, combined with the spectral compensation technique. A simulation was conducted to verify the effectiveness of the method.