• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.553-558
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• 1998

We present in this paper the ture union bound of the performance of chip level detection for coded DS/CDMA system operating in Rician fading channels such as LEO satellite mobile radio where the maximum doppler frequency is very high. The main objective of this paper is to calculate the exact doe union bound of BER performance of different performance of different quadrature detectors and to find a optimum spreading factor as a function of fade rate. The rationale of using multiple chip detection is to reduce the effective fade rate or variation. We considered chip level differential detection, chip level maximum likelihood sequence estimation, noncoherent detection and coherent detection with perfect channel state information as a reference.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.43-49
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• 2014

In this paper, we consider the performance evaluation of space time block code (STBC)) with coordinate interleaved orthogonal design (CIOD) over time selective channel. In case of quasi static channel, STBC-CIOD satisfies full rate and full diversity (FRFD) property with the single symbol decoding. However in the time selective channel, the symbol interference degrades the system performance when we employ the single symbol decoding. We derive the union bound of the symbol error probability by evaluating the pairwise error probability in the first order Markov channel. We also present simulation results of STBC-CIOD with QPSK.

• Journal of Labour Economics
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• v.37 no.3
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• pp.45-73
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• 2014

This study analyzes the effect of labor unions in Korean manufacturing industry on wage variance of men from 1988 to 2012. The results are as follows. Firstly, the wage variance within establishments is higher than that between establishments, and the wage variance between establishments in the non-union sector has increased significantly compared to that in the union sector since 2000. There is strong evidence that the latter is due to the solidarity wage policy of unions which has strengthened since the early 2000s. Secondly, the influence of labor unions on the wage structure within the union sector has gotten stronger recently despite the general drop in the labor union membership. Thirdly, since the mid-1990s labor unions have contributed to reducing the overall wage variance. It implies that decline in the unionization rate over the years in Korea is likely to have contributed to increasing wage inequality.

• The KIPS Transactions:PartB
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• v.14B no.4
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• pp.255-262
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• 2007

This paper proposes an enhanced skin color-based detection method to find a region of human face in color images. The proposed detection method combines three color spaces, RGB, $YC_bC_r$, YIQ and builds color union histograms of luminance and chrominance components respectively. Combined color union histograms are then fed in to the back-propagation neural network for training and Levenberg-Marquadt algorithm is applied to the iteration process of training. Proposed method with Levenberg-Marquadt algorithm applied to training process of neural network contributes to solve a local minimum problem of back-propagation neural network, one of common methods of training for face detection, and lead to make lower a detection error rate. Further, proposed color-based detection method using combined color union histograms which give emphasis to chrominance components divided from luminance components inputs more confident values at the neural network and shows higher detection accuracy in comparison to the histogram of single color space. The experiments show that these approaches perform a good capability for face region detection, and these are robust to illumination conditions.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.671-676
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• 2014

Objective: The objective of this study was to establish a program model for use in wide-spread cervical cancer screening. :Methods: Cervical cancer screening was conducted in Zhongshan city in Guangdong province, China through a coordinated network of multiple institutes and hospitals. A total of 43,567 women, 35 to 59 years of age, were screened during regular gynecological examinations using the liquid-based ThinPrep cytology test (TCT). Patients who tested positive were recalled for further treatment. Results: The TCT-positive rate was 3.17%, and 63.4% of these patients returned for follow-up. Pathology results were positive for 30.5% of the recalled women. Women who were younger than 50 years of age, urban dwelling, low-income, had a history of cervical disease, began having sex before 20 years of age, or had sex during menstruation, were at elevated risk for a positive TCT test. The recall rate was lower in women older than 50 years of age, urban dwelling, poorly educated, and who began having sex early. Ahigher recall rate was found in women 35 years of age and younger, urban dwelling, women who first had sex after 24 years of age, and women who had sex during menstruation. The positive pathology rate was higher in urban women 50 years of age and younger and women who tested positive for human papillomavirus. Conclusion: An effective model for large-scale cervical cancer screening was successfully established. These results suggest that improvements are needed in basic education regarding cervical cancer screening for young and poorly educated women. Improved outreach for follow-up is also necessary to effectively control cervical cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1887-1893
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• 2012

The aim of this study was to detail characteristics of mammary Paget's disease (PD) representing the whole population in China. A total of 4211 female breast cancer inpatients at seven tertiary hospitals from seven representative geographical regions of China were collected randomly during 1999 to 2008. Data for demography, risk factors, diagnostic imaging test, physical examination and pathologic characters were surveyed and biomarker status was tested by immunohistochemistry. The differences of demography and risk factors between PD with breast cancer and other lesions were compared using Chi-square test or t-test, with attention to physical examination and pathological characters. The percentage of PD was 1.6% (68/4211) in all breast cancers. The mean age at diagnosis was 48.1, and 63.2% (43/68) patients were premenopausal. There is no difference in demography and risk factors between PD with breast cancer and other breast cancer (P > 0.05). The main pattern of PD in physical exam and pathologic pattern were patients presenting with a palpable mass in breast (65/68, 95.6%) and PD with underlying invasive cancer (82.4%, 56/68) respectively. The rate of multifocal disease was 7.4% (5/68). PD with invasive breast cancer showed larger tumor size, more multifocal disease, lower ER and PR expression and higher HER2 overexpression than those in other invasive breast cancer (P < 0.05). These results suggested that PD in China is a concomitant disease of breast cancer, and that PD with underlying invasive cancer has more multiple foci and more aggressive behavior compared with other breast invasive cancer. We address the urgent needs for establishing diagnostic and therapeutic guidelines for mammary PD in China.

• Journal of Korean Society of Forest Science
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• v.99 no.2
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• pp.220-225
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• 2010

This study was conducted to examine the effects of wound dressing with thiophanate-methyl paste on the compartmentalization of pruning wounds in Acer palmatum. A total of thirty field-grown trees were used for three different treatments, such as no dressing, dressing once right after pruning cut, and dressing twice, one more dressing treatment one year after initial dressing. Wound closure rate (WCR) and discolored/wound area ratio (D/W ratio) two years after treatment were measured. Variations of extractives, holocellulose and lignin at the treated branch unions were also examined. The WCR of no dressing treatment of 70.9% was significantly lower than those of the two dressing treatments (85.4% and 82.7%, respectively), while the difference between dressing once and twice was not significant. The D/W ratio of no dressing treatment (39.3%) was significantly higher than those of the two dressing treatments (around 30%). Generally, at the branch core of the treated union, contents of extractives and lignin were higher and holocellulose contents were lower than the branch core of the union with living branch. Among the branch core of treated union, no dressing treatment showed a relatively lower holocellulose (63.5%), and relatively higher extractives (2.8%) and lignin (26.6%) than dressing once (66.2%, 1.7%, 26.1%, respectively).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.11
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• pp.1-8
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• 2008

In this paper, we analyze the symbol error rate (SER) performance of maximum likelihood (ML) joint detection in downlink multiple-input multiple-output (MIMO) multicarrier code division multiple access (MC-CDMA) systems by deriving a tight union bound on the symbol error rate (SER). The union bound for ML joint detection is utilized to demonstrate the performance of MIMO MC-CDMA systems quantitatively in multiuser and frequency selective Rayleigh fading environments. An analysis of the diversity order of the systems shows the effects of multiple users, spread subcarriers, and multiple antennas on the ML joint detection performance. Furthermore, the analysis shows that MIMO MC-CDMA systems without full loading can achieve more diversify than MIMO orthogonal frequency division multiplexing (OFDM) systems.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7219-7222
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• 2014

Background: Early gastric cancer (EGC) is well accepted as having a favorable prognosis, but some patients experience an ominous outcome after curative resection. This study was aimed at evaluating predictive factors associated with prognosis of D2 gastrectomies in patients with early gastric cancer. Materials and Methods: A total of 518 patients with early gastric cancer who underwent D2 gastrectomies were reviewed in this study. The clinicopathological features and surgical outcomes were analyzed. The survival rate was estimated using the Kaplan-Meier method and compared by log rank test. Prognostic factors were analyzed using a multivariate Cox proportional hazards model. Results: The 5-year survival rate was 90.3%. Tumor infiltration, lymph node metastasis and lymphovascular invasion were significant prognostic factors for survival. Gender, age, tumor size, tumor location, macroscopic type and histological type were not significant prognostic factors. Multivariate analysis indicated that lymph node metastasis was an independent poor prognosis factor. Conclusions: Early gastric cancers with lymph node metastasis have a relatively poor prognosis after standard surgery. Even after curative resection, patients with EGC with positive lymph nodes should be closely followed and be considered as candidates for comprehensive therapies.

• Journal of the Korean Orthopaedic Association
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• v.55 no.2
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• pp.169-177
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• 2020

Purpose: To assess the effectiveness of mixed grafts in lumbar posterolateral fusion (PLF) by comparing the bone union rates of an autobone with a bone substitute mixed graft. Materials and Methods: The patients were followed-up for at least two years after PLF and divided into four groups according to the mixed graft retrospectively. Group I was 48 cases using a femoral head allobone. Group II was 38 cases using β-tricalcium phosphate. Group III was 92 cases using biphasic calcium phosphate. Group IV was 38 cases using biphasic calcium phosphate and autologous bone marrow. Union was evaluated by the work up simple radiographs after two years from PLF. Union was defined if the radiographs demonstrated a bilateral continuity in the fusion mass between the cephalad and caudal transverse processes with less than 2° of angular motion and no translation between the vertebrae at the level of fusion on the lateral flexion-extension radiographs. Results: According to simple radiographs after two years from PLF, the rate of union was highest in Group IV using local autobone, biphasic calcium phosphate and autologous bone marrow mixed graft. Conclusion: Biphasic calcium phosphate is an osteoconductive bone substitute that increases the bio-absorbability and mechanical strength. Autologous bone marrow has osteoinductive and osteogenic properties. These features can increase the rate of bone union. Therefore, a local autobone, biphasic calcium phosphate and autologous bone marrow mixed graft can be considered an effective bone graft substitute for lumbar PLF instead of an autobone graft.