• Journal of KIISE:Databases
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• v.28 no.3
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• pp.458-467
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• 2001

Optimistic Two-Phase Locking(O2PL) performs as well as or better than the other approaches because it exploits client caching well and also has relatively lower network bandwidth requirements. However, O2PL leads to unnecessary waits, because, it can not be commit a transaction until the transaction obtains all requested locks. In addition, Optimistic Concurrency Control(OCC) tends to make needless aborts. This paper suggests an efficient optimistic cache consistency protocol that overcomes such shortcomings. Our scheme decides whether to commit or abort a transaction without wait and it adopts transaction re-ordering in order to minimize the abort rate. Our scheme needs only one version for each data item in spite of the re-ordering mechanism used. Finally, this paper presents a simulation-based analysis that shows superiority in performance of out scheme to O2PL and OCC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1A
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• pp.134-141
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• 2007

This paper presents a frequency synthesizer(FS) for 5.2GHz/2.4GHz dual band wireless applications which is designed in a standard $0.18{\mu}m$ CMOS1P6M process. The 2.4GHz frequency is obtained from the 5.2GHz output frequency of Voltage Controlled Oscillator (VCO) by using the Switched Capacitor (SC) and the divider-by-2. Power dissipations of the proposed FS and VCO are 25mW and 3.6mW, respectively. The tuning range of VCO is 700MHz and the locking time is $4{\mu}s$. The simulated phase noise of PLL is -101.36dBc/Hz at 200kHz offset frequency from 5.0GHz with SCA circuit on.

• Clinics in Shoulder and Elbow
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• v.19 no.1
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• pp.2-7
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• 2016

Background: The purpose of this study is to compare the radiological and clinical outcomes after open reduction and plate fixation of midshaft clavicle fractures between patients who achieved successful anatomical reduction and those who had a remaining fracture gap even after open reduction and plate fixation, and were thus treated with additional demineralized bone matrix (DBM). Methods: This retrospective analysis was conducted on 56 consecutive patients who underwent open reduction and internal fixation using a locking compression plate for acute displaced midshaft clavicle fractures, and who underwent radiographic and clinical outcome evaluations at least 6 months postoperatively. The outcomes between those who achieved perfect anatomical reduction without remnant gap (n=32) and those who had a remaining fracture gap even after open reduction and plate fixation treated with additional DBM (n=24) were evaluated. Results: There were no differences in the use of lag screws or wiring and operation time (all p>0.05) between those with and without remnant gap. No difference in the average radiological union time and clinical outcomes (satisfaction and Constant score) was observed between the two groups (all p>0.05). However, significantly faster union time was observed for AO type A fracture compared with other types (p=0.012), and traffic accident showed association with worse clinical outcomes compared with other causes of injury. Conclusions: Surgical outcome of midshaft clavicle fracture was more affected by initial fracture type and event, and re-reduction and re-fixation of the fracture to obtain a perfect anatomical reduction spending time appears to be unnecessary if rigid fixation is achieved.

• Clinics in Shoulder and Elbow
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• v.20 no.3
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• pp.153-161
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• 2017

Background: This study was conducted to compare the clinical and radiological outcomes of the locking hook plate fixation (HP) technique and the single tight rope (TR) technique applied for acute high-grade acromioclavicular (AC) joint separations. Methods: Between 2009 and 2014, 135 consecutive patients with acute AC joint separation Rockwood types III, IV, and V were subjected to surgical reconstruction. One hundred fourteen patients (84.4%) were available for retrospective evaluation. Of them, 62 and 52 were treated using the single TR group and clavicular HP group techniques, respectively. The visual analogue scale, Constant, American Shoulder and Elbow Surgeons (ASES), and Taft scores were used for clinical assessment. Postoperative shoulder range of motion was also assessed. An anteroposterior radiograph of the coracoclavicular distance (CCD) was obtained to evaluate the radiographic signs of recurrence. Results: The TR group patients had better Constant, ASES, and Taft scores than the HP group patients. The loss of reduction in terms of the CCD did not differ between groups. Subacromial osteolysis was observed in 34.6% of the cases in the HP group. However, there were no significant differences in the clinical outcomes between the patients with and without osteolysis in the HP group. Subcoracoid osteolysis, drill tunnel widening, and metal displacement were observed in 3.2%, 22.6%, and 4.8% of the cases in the TR group, respectively. Conclusions: The single TR technique was relatively more effective at treating acute high-grade AC joint injuries than the HP fixation technique (level of evidence: therapeutic; retrospective comparative study, Level III).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2661-2669
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• 2010

In this study, a finite element formulation based first-order shear deformation theory is developed for non-linear behaviors of laminated composite plates containing matrix cracking. The multi-directional stiffness degradation is developed for adopting the stiffness variation induced from matrix cracking, which is proposed by Duan and Yao. The matrix cracking can be expressed in terms of the variation of material properties, such as Young's modulus, shear modulus and Possion ratio of plates, and sequently it is possible to predict the variation of the local stiffness. Using the assumed natural strain method, the present shell element generates neither membrane nor shear locking behavior. Numerical examples demonstrate that the present element behaves quite satisfactorily either for the linear or geometrical nonlinear analysis of laminated composite plates. The results of laminated composite plates with matrix cracking may be the benchmark test for the non-linear analysis of damaged laminated composite plates.

• The Journal of Information Technology
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• v.3 no.3
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• pp.117-134
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• 2000

Client-server DBMS based on a data-skipping model can exploit client resources effectively by allowing inter-transaction caching. However, inter-transaction caching raises the need of transactional cache consistency maintenance(TCCM) protocol, since each client is able to cache a portion of the database dynamically. Detection-based TCCM schemes can reduce the message overhead required for cache consistency if they validate clients replica asynchronously, and thus they cm show high throughput rates. However, they tend to show high ratios of transaction abort since transactions can access invalid replica. For coping with this drawback, this paper develops a new notion of shadow transaction, which is a backup-purpose one that is kept ready to replace an aborted transaction. This paper proposes a new detection-based TCCM scheme named DL-ST on the basis of the notion of shadow transaction. Using a simulation model, this paper evaluates the effect of shadow transaction in terms of transaction through rate and abort ratio.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.5
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• pp.674-682
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• 2009

The modular robot is one which was developed to get over limit of the space movement for the mobile robot. The chain type robot in particular is connected by series each other and this form expression method is simple and easy to really make a docking method efficiently. However, the related studies were focused on the movement that used to be combination, and the movement of a cell independent mainly does not consist and have a problem to dock only in a direction, not to be connected with all directions. Therefore, we suggested a modular structure for quick, independent movement to solve such a problem and had own autonomy. In addition, we are intended to get some effectiveness for connection mechanism using one locking motor. In this paper, we dealt with the design for the mechanical and electrical points and docking algorithm including communication method. All of the structure is verified with real action experiment through the shape expressions of various application platform.

• Clinics in Orthopedic Surgery
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• v.10 no.4
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• pp.462-467
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• 2018

Background: Significant discrepancy exists between anatomical plate designs and the anatomy of the native distal radius, which may be attributable to considerable morphometric variations in the volar aspect of the distal radius. We aimed to evaluate the degree of variability in the morphometry of the distal radius and identify factors associated with this variability. Methods: We measured the volar surface angle (VSA) of the intermediate and lateral columns and the volar surface width (VSW) in the distal radius from three-dimensional computed tomography scans acquired from 81 cadaveric forearms. These morphometric parameters were compared between the lateral and intermediate columns, between males and females, and between Koreans and Caucasians. Caucasian morphometric data were obtained and pooled from the previous studies. The coefficient of variation was used to assess the variability of the parameters and Cohen's d to estimate the effect size of the difference between groups. Results: The average VSA of the lateral column was $22^{\circ}{\pm}6^{\circ}$, and that of the intermediate column was $29^{\circ}{\pm}8^{\circ}$ in Koreans (p < 0.001). The variability was high for both VSAs. The VSA of the intermediate column was significantly larger in males than in females (p < 0.001) and in Caucasians than in Koreans (p < 0.001). The average VSW of distal radius was $30{\pm}3mm$ at the watershed line, and it became narrower proximally. The VSW was significantly larger in males than in females (p < 0.001) and in Koreans than in Caucasians (p < 0.001). The effect sizes of the difference for the VSA and VSW between sexes, races and columns were medium to large. Conclusions: Considerable variability exists in the morphometry of the volar distal radius, with sex, race, and column as contributing factors. These results suggest that surgeons should carefully choose an anatomical volar locking plate with appropriate angulation characteristics for each patient to achieve patient-specific alignment of the distal radius.

• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.447-454
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• 2006

We obtained analytic solutions of boundary conditions to the stable region of Z-fold $Cr^{4+}$ : YAG laser cavity when the conditions are with and without thermal tensing effect. Also we investigated the influence of the thermal tensing effect on the stability of cavity, beam waist, and astigmatic compensation using aberration transformation matrices. The thermal tensing effect almost has no influence on the stable region of the cavity when the crystal is located in the middle of two concave mirrors and when the distances from the concave mirror to the reflecting mirror and the output coupler are the same. The beam waist, however, is affected more in a tangential plane than in a sagittal plane, and so it is difficult to have astigmatic compensation when the thermal tensing effect exists. This result means that the thermal tensing effect should be considered even for the Kerr-lens mode-locking.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.6
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• pp.507-515
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• 2018

The results of the survey on water utilization status, the wasted water factor, the awareness, and the education and promotional activities of water saving in Daejeon City are as follows: The percentage of using tap valve with a closure was 66% when showering. 74% of water was used with closing the tap valve when washing faces with no water needed, it was still considered that there existed a wasting water. The most wasting reasons of water were found to be shower, bath, and laundry in order. In the awareness of practicing tap water saving, 9.1% of respondents acted actively, 53.4% of them were trying to practice it, and more than 63% had a positive awareness. In the contents of practicing saving water, locking water when soaping while showering, non-laundry of small quantity, and using cups when brushing teeth were top priorities. About 50% of the reasons for saving water was to practice purely saving water, when saving for economic help was excluded. The level of water saving awareness was not high when considering that the ratio of usage without water saving equipment and installation, and using method was relatively high when moving in. In order to make usage of water saving equipment more common, it was deemed necessary to provide information on the purchase of water saving equipment and to promote and educate the efficiency of saving of related products. More than about 90% of the respondents responded that water saving education or promotional activities had an effect of improving water saving awareness. The most effective method of education and promotional activities was found to be 40.4% by mass media activities, and 21.7% by promotions through mobile devices.