• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2B
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• pp.71-79
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• 2006

Address lookup is an essential function in the Internet routers, and it determines overall router performance. In this paper, we have thoroughly investigated the binary-search-based address lookup algorithms and proposed a new algorithm based on binary search on prefix lengths. Most of the existing binary search schemes perform binary search on prefix values, and hence the lookup speed is proportional to the length of prefixes or the log function of the number of prefixes. The previous algorithm based on binary search on prefix lengths has superior lookup performance than others. However, the algorithm requires very complicated pre-computation of markers and best matching prefixes in internal nodes since naive binary search is not possible in their scheme. This complicated pre-computation makes the composition of the routing table and incremental update very difficult. By using leaf-pushing, the proposed algorithm in this paper removes the complicated pre-computation of the Previous work in performing the binary search on prefix lengths. The performance evaluation results show that the proposed scheme has very good performance in lookup speed compared with previous works.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.778-785
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• 2010

The folded monopole antenna for applying mobile communications equipment and wireless devices is presented in this paper. By using the coplanar waveguide feed the operating bandwidth has improved. In addition, each individual resonant elements has occurred different capacitance through asymmetrical left and right ground planes; therefore, the bandwidth has kept and the impedance matching has stabilized. By measurement results, the impedance bandwidth under VSWR< 2.5:1 are $824{\sim}890$ MHz and the $1,500{\sim}2,170$ MHz, also radiation patterns has omni-directional characteristics. The maximum gains of the proposed antenna are 5.52, 0.64, 3.00, 0.94 and 1.85 dBi at 850, 1,575, 1,790, 1,930 and 2,050 MHz respectively. The proposed antenna will be adapted to the internal antenna of the mobile communication devices.

• Journal of Korean Neurosurgical Society
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• v.62 no.2
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• pp.217-224
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• 2019

Objective : We attempted to discover that Ankylosing spondylitis (AS) has a comprehensive relationship with congestive heart failure and death. Methods : We used a nationwide database managed by the Korean National Health Insurance Service from 2010 to 2014. Twelve thousand nine hundred eighty-eight patients with a diagnosis of AS and 64940 age- and sex- stratified matching subjects without AS were enrolled in the AS and control groups. Incidence probabilities of 6 years congestive heart failure and death in each group were calculated. The Cox proportional hazard regression analysis was used to estimate the hazard ratio. We divided the AS and control groups into subgroups according to sex, age, income, and comorbidities. Results : During the follow-up period, 102 patients (0.79%) in the AS group and 201 patients (0.32%) in the control group developed congestive heart failure (p<0.0001). In addition, 211 (1.62%) subjects in the AS group died during the follow-up period compared to 639 (0.98%) subjects in the control group (p<0.0001). The adjusted hazard ratio of congestive heart failure and death in the AS group was 2.28 (95% confidence interval [CI], 1.80-2.89) and 1.66 (95% CI, 1.42-1.95), respectively. The hazard ratios of congestive heart failure and death were significantly increased in all of the subgroups. Conclusion : The incidence rates of congestive heart failure and death were increased in AS patients.

• Archives of Plastic Surgery
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• v.46 no.2
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• pp.140-146
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• 2019

Background Thoracodorsal vessels (TDVs) and internal mammary vessels (IMVs) have both been widely employed as recipient vessels for use in free muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM) flaps. However, whether TDVs or IMVs are preferable as recipient vessels for autologous breast reconstruction with a free MS-TRAM flap remains controversial. The purpose of this study was to compare the clinical outcomes when TDVs were used as recipient vessels to those obtained when IMVs were used as recipient vessels for autologous breast reconstruction with a free MS-TRAM flap. Methods A retrospective matched-cohort study was performed. We retrospectively reviewed data collected from patients who underwent a free MS-TRAM flap for autologous breast reconstructions after mastectomy between March 2003 and June 2013. After a one-to-one matching using age, 100 autologous breast reconstructions were selected in this study. Of the 100 breast reconstructions, 50 flaps were anastomosed to TDVs and 50 to IMVs. Patient demographics and clinical outcomes including operation time, length of hospital stay, postoperative complications, and aesthetic score were compared between the two groups. Results No statistically significant differences were found between the two groups in patient demographics and clinical outcomes, including the complication rates and aesthetic scores. There were no major complications such as total or partial flap loss in either group. Conclusions The results of our study demonstrate that both TDVs and IMVs were safe and efficient as recipient vessels in terms of the complication rates and aesthetic outcomes.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.1
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• pp.1-11
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• 2021

Purpose : The purpose of this study was to investigate the effect of single limb stance exercise according to the support surface on dynamic balance ability and abdominal muscle thickness. Methods : We recruited 28 healthy subjects in this study. Subjects were assigned to 2 groups by matching method. The control group was 5 males and 9 females, and single limb stance exercise was performed on the stable support surface. The experimental group consisted of 6 males and 8 females, and trained to stand on the unstable support. During the single limb stance exercise, the dominant foot was set as the foot that appeared numerically through the exercise of the dynamic balance meter (Biorescue). Single limb stance exercise along the supporting surface was maintained for 15 seconds and then rested for 15 seconds. It was repeated 5 times. Particularly, the balance exercise on the unstable support surface was sufficiently practiced. Independent t test was performed for comparison between groups. Paired t test was performed to compare before and after each group. Results : There was no difference between the control group and the experimental group in the comparison of dynamic balance ability (p>.05). However, there were significant differences before and after exercise in both the control and experimental groups (p<.05). Similarly, in the comparison of abdominal muscle thickness, there was a significant difference within each group, especially internal oblique and transverse abdominis (p<.05), and no difference between groups (p>.05). Conclusion : Based on these results, although there was no difference between the groups, in the experimental group, numerical increase in dynamic balance ability and abdominal muscle thickness was confirmed. Therefore, single limb stance exercise on the unstable support surfaces activates core muscles and has a positive effect on dynamic balancing ability.

• Korean Journal of Optics and Photonics
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• v.33 no.6
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• pp.260-266
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• 2022

A diffraction grating structure composed of two matching layers and two grating layers was formed, and a diffraction grating with high transmission diffraction efficiency in the -1st order was designed through an optimization technique. The designed diffraction grating had a transverse electric wave diffraction efficiency of 99.997% at the design center wavelength, and had a wavelength width of 80 nm and an incident angle width of 20.0° that maintained a diffraction efficiency of 95% or more. By performing the grating tolerance analysis, it was confirmed that the thickness tolerance for a diffraction efficiency of 95% or more was secured to at least 60 nm, and the diffraction efficiency could be maintained even in a trapezoidal shape with an internal angle of less than 10°.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.61-67
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• 2021

In this paper, we propose a method of extracting and recognizing related information for research from images of the unstructured pulmonary function test papers using character detection and recognition techniques. Also, we develop a post-processing method to reduce the character recognition error rate. The proposed structuring method uses a character detection model for the pulmonary function test paper images to detect all characters in the test paper and passes the detected character image through the character recognition model to obtain a string. The obtained string is reviewed for validity using string matching and structuring is completed. We confirm that our proposed structuring system is a more efficient and stable method than the structuring method through manual work of professionals because our system's error rate is within about 1% and the processing speed per pulmonary function test paper is within 2 seconds.

• Asia pacific journal of information systems
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• v.30 no.3
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• pp.568-589
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• 2020

Recently, Social media has become a concern for businesses, including Small and Medium Enterprises (SMEs). SMEs began to adopt social media to support their performance. To benefit from the application of social media, SMEs must implement the right strategy. This study aims to analyze the factors that influence the use of social media in SMEs. Furthermore, alignment between social media functionalities and strategies and their effect on SME's performance are investigated. A case study is conducted in Gymi, a garment SMEs in East Java, Indonesia. The data collection includes interviews with the owner of SMEs, observations, and document analysis. Data analysis is performed by pattern matching, which matches the patterns from the literature with data from the case study. The results of this study show that cost-effectiveness, interactivity, and compatibility are factors that influence the use of social media in Gymi. The social media used by Gymi are Instagram, Facebook, YouTube, WhatsApp, and LINE. However, the main social media used to support Gymi's functions is Instagram. Gymi has a relatively good social media strategy as it has defined a specific goal, target audience, and channel selection for social media (Instagram). It also has specific resources and policies to handle social media. Gymi monitors and evaluates their social media content activities. These strategies are aligned with the Instagram feature used to support Gymi's function, particularly marketing, sales, customer service, and to some extent, internal operation. The alignment contributes to Gymi's performance measured by the increase in reputation (number of Instagram followers) and sales.

• Computers and Concrete
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• v.33 no.5
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• pp.535-544
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• 2024

In the rapidly advancing landscape of computer vision (CV) technology, there is a burgeoning interest in its integration with the construction industry. Camera calibration is the process of deriving intrinsic and extrinsic parameters that affect when the coordinates of the 3D real world are projected onto the 2D plane, where the intrinsic parameters are internal factors of the camera, and extrinsic parameters are external factors such as the position and rotation of the camera. Camera pose estimation or extrinsic calibration, which estimates extrinsic parameters, is essential information for CV application at construction since it can be used for indoor navigation of construction robots and field monitoring by restoring depth information. Traditionally, camera pose estimation methods for cameras relied on target objects such as markers or patterns. However, these methods, which are marker- or pattern-based, are often time-consuming due to the requirement of installing a target object for estimation. As a solution to this challenge, this study introduces a novel framework that facilitates camera pose estimation using standardized materials found commonly in construction sites, such as concrete forms. The proposed framework obtains 3D real-world coordinates by referring to construction materials with certain specifications, extracts the 2D coordinates of the corresponding image plane through keypoint detection, and derives the camera's coordinate through the perspective-n-point (PnP) method which derives the extrinsic parameters by matching 3D and 2D coordinate pairs. This framework presents a substantial advancement as it streamlines the extrinsic calibration process, thereby potentially enhancing the efficiency of CV technology application and data collection at construction sites. This approach holds promise for expediting and optimizing various construction-related tasks by automating and simplifying the calibration procedure.

• Information Systems Review
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• v.17 no.2
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• pp.29-48
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• 2015

This study proposes an integrated operational model of branches with customer center at stock brokerage firms and suggests ways to improve existing systems. This suggested integrated model of branches and customer centers can increase customer satisfaction and customer values for the specific services at each channel. This integrated model also enables customers to make transactions at a desired specific time, make it possible to inquire whatever the customer wished to ask, and select desired contact channels. In addition, the firms can bring in improved effectiveness of internal resources by integrating all the resources the firm has. Personal resources and system resources are distributed by the characteristics of channels that can be selected by the customers. Then agents also can provide more speedy and accurate responses to the engaged customer interactions matching to his/her job in charge. Also, the model makes it possible to collect the latest customer and transaction information at the moment of each interactions, by which the firm can provide customized services specifically tailed to each customers' preferences. However, systematic interactions between branches and customer center, and completed system should be equipped with in order to provide the highest quality services.