• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.7
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• pp.23-31
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• 2012

Resource allocation, such as joint rate control and scheduling, is an important issue in cognitive radio networks. However, it is difficult to jointly consider the rate control and scheduling problem due to the stochastic behavior of channel availability in cognitive radio networks. In this paper, we propose an asymmetric joint rate control and scheduling technique under reliability constraints in cognitive radio networks. The joint rate control and scheduling problem is formulated as a convex optimization problem and substantially decomposed into several sub-problems using a dual decomposition method. An algorithm for secondary users to locally update their rate that maximizes the utility of the overall system is also proposed. The results of simulations revealed that the proposed algorithm converges to a globally optimal solution.

• Korean Journal of Veterinary Research
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• v.20 no.2
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• pp.123-125
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• 1980

Ununited Anconeal Process (UAP) is defined as a disease of young dogs due to developmental abnormality in which there is a seperation of the anconeal process from the diaphysis of the ulna, leading to a front leg lameness and secondary osteoarthritis. A six -year-old German Shepherd dog was presented because of intermittent right front leg lameness. Diagnosis was made of ununited anconeal process with moderate osteoarthritis by radiographic examination. Surgical removal of ununited anconeal process and curettage of osteoarthritic growth within the elbow joint relieved significant clinical signs despite of size and age of the dog.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.3
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• pp.204-211
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• 2007

Experiments were conducted to investigate the failure and strengths of carbon composite-to-aluminum single-lap bonded joints with 5 different bonding lengths. Joint specimens were fabricated to have secondary bonding of laminate and aluminum with a film type adhesive, FM73m. Tested joints have the bonding strengths between the values of aluminum-to-aluminum joints and composite-to-composite joints. In the joints with bonding length-to-width ratio smaller than 1, the strength decreases as the bonding length increases. In the joints with the ratio larger than 1, however, the strength converges to a constant value. Final failure mode of all the specimens was delamination. To use the maximum strength of the adhesive, it is important to design the joint to have strong resistance to delamination.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.8
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• pp.751-758
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• 2009

Failure strengths of composite single-lap adhesive joints were investigated with various parameters such as manufacturing method, overlap length and adherend thickness. A total of 335 single-lap joint specimens were tested under tension. Specimens were fabricated with 4 different manufacturing processes; cocuring without and with adhesive, secondary bonding and co-bonding. Each manufacturing process has 5 different overlap lengths and 4 different thicknesses, respectively. As expected, failure strength is higher in thicker adherend joints and lower in larger overlap length specimens. Interesting result is that the secondary bonded joints show the higher strength than the cobonded and cocured joints with adhesive, and give close or even higher strength compared with non-adhesive cocured case.

• Advances in concrete construction
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• v.11 no.5
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• pp.375-386
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• 2021

In this paper, a study of stability and health of a newly-built railway tunnel is presented. The field test was implemented to monitor the secondary lining due to the significant cracking behaviors influenced the stability and health of the tunnel structure. Surface strain gauges were installed for monitoring the status of crack openings, and the monitoring outputs demonstrated that the cracks were still in the developing stage. Additionally, adjacent tunnel and poor condition of surrounding rock were identified as the causes of the lining cracking by systematically characterizing the crack spatial distribution, tunnel site and surrounding rock conditions. Reconstruction of partial lining and reconstruction of the whole secondary lining were designed as the maintenance projects for different cracking regions based on the construction feasibility. For assessing the health conditions of the reinforced lining, embedded strain gauges were set up to continuously measure the strain and the internal force of the reconstructed structures. For the partially reconstructed lining, the outputs show the maximum tensile elongation is 0.018 mm during 227 days, which means the structure has no obvious deformation after maintenance. The one-year monitoring of full-section was implemented in the other two completely reconstructed cross-sections by embedded strain gauge. The outputs show the reconstructed secondary lining has undertaken the pressure of surrounding rock with the time passing. According to the calculated compressive and tensile safety factors, the completely reconstructed lining has been in reliable and safe condition during the past year after reinforcement. It can conclude that the aforementioned maintenance projects can effectively ensure the stability and health of this tunnel.

• Journal of Biomedical Engineering Research
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• v.33 no.2
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• pp.78-88
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• 2012

Knee joint instability by anterior cruciate ligament(ACL) rupture is allowing the abnormal loading condition at the tibial epiphysis locally, resulting in producing locally different bone bruise. The study examined difference between local alteration patterns of trabecular bone microarchitecture at medial and lateral parts of the tibial epiphysis by ACL rupture. Fourteen SD rats were divided into Control(CON; n = 7) and Anterior Cruciate Ligament Transection(ACLT; n = 7) groups. The tibial joints were then scanned by in vivo ${\mu}$-CT at 0, 4, and 8 weeks post-surgery. The results showed that alteration pattern on trabecular bone microarchitecture at medial part was significantly higher than that at lateral part of the tibial epiphysis in ACLT group from 0 to 8 weeks(P < 0.05). Tb.Th and Tb.Sp distributions were well corresponded with differences between aforementioned trabecular bone microarchitectural alteration pattens at medial and lateral parts of the tibial epiphysis in ACLT group from 0 to 8 weeks(P < 0.05). These findings suggest that the alteration patterns of trabecular bone microarchitecture should be locally and periodically considered, particularly with respect to the prediction of bone fracture risk by ACL rupture. Improved understanding of the alteration patterns at medial and lateral trabecular bone microarchitectures at the tibial epiphysis may assist in developing more targeted treatment interventions for knee joint instability secondary to ACL rupture.

• The Korean Journal of Pain
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• v.9 no.2
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• pp.390-394
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• 1996

Background: Occipital neuralgia is characterized by pain, usually deep and aching, in the distribution the second and/or third cervical dorsal root. Two broad groups of patients include primary occipital neuralgia with no apparent etiology and secondary neuralgia with structural pathology. Patients with occipital neuralgia can develop autonomic changes and hyperesthesia. In patients who have not improved with conservative treatment, we have carried out various nerve blocks and evaluated the effectiveness. Methods: In a series of 20 occipital neuralgia patients with no apparent etiolgy, we have carried out great occipital nerve blocks with needle TEAS. In patients who have not improved more than 75% on VAS with great occipital block, we have carried out C2 ganglion blocks and in patients who have not improved more than 75% with C2 ganglion block, C3 root blocks, C2/C3 facet joint blocks have been carried out in due order. Results: In 3 patients out of 10 patients who have not improved with great occipital nerve block, C2 ganglion block led to pain relief. A good response of C3 root block was achived in 2 of 7 patients without response to C2 ganglion block and C2/C3 facet joint block led to improvement in 1 of 5 patients without response to C3 root block. Conclusions: Nerve blocks like great occipital nerve block, C2 ganglion block, C3 root block, or C2/C3 facet joint block were effective in the patients who have not improved with conservative treatment.

• Journal of muscle and joint health
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• v.21 no.3
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• pp.195-205
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• 2014

Purpose: This study was conducted to identify factors that influence health-related quality of life in older adults with osteoarthritis. Methods: This study used a cross-sectional design with secondary analysis of the Korean National Health and Nutrition Examination Survey 2011. A total of 362 participants aged 65 years and older who had osteoarthritis were selected. Health-related quality of life using EQ-5D, perceived health status, body mass index, numbers of chronic illness, smoking and alcohol use, exercise, activity limitation, joint pain and stiffness, depression, and perceived stress were measured. Descriptive statistics, $x^2$-test, t-test, ANOVA, Pearson's correlation coefficients, and multiple regression were conducted with SPSS/WIN 21.0. Results: The mean score of EQ-5D was 0.77 in older adults with osteoarthritis. The results of multiple regression analysis showed that age, income, subjective health status, restriction of activity, knee joint stiffness, depressive mood, and perceived stress significantly predicted health-related quality of life in older adults with osteoarthritis, explaining 42% of the variance. Conclusion: Older adults with osteoarthritis have low health-related quality of life. In oder to improve health-related quality of life in older adults with osteoarthritis, it is important not only to enhance physical function but also to provide emotional support.

• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.3
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• pp.159-172
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• 2015

Treatment of polymicrobial infected musculoskeletal defects continues to be a challenge in orthopaedics. This research investigated single and dual-delivery of two antibiotics, vancomycin and amikacin, targeting different classes of microorganism from a biodegradable calcium sulfate-chitosan-nHA microsphere composite scaffold. The addition of chitosan-nHA was included to provide additional structure for cellular attachment and as a secondary drug-loading device. All scaffolds exhibited an initial burst of antibiotics, but groups containing chitosan reduced the burst for amikacin at 1hr by 50%, and vancomycin by 14-25% over the first 2 days. Extended elution was present in groups containing chitosan; amikacin was above MIC ($2-4{\mu}g/mL$, Pseudomonas aeruginosa) for 7-42 days and vancomycin was above MIC ($0.5-1{\mu}g/mL$ Staphylococcus aureus) for 42 days. The antibiotic activity of the eluates was tested against S. aureus and P. aeruginosa. The elution from the dual-loaded scaffold was most effective against S. aureus (bacteriostatic 34 days and bactericidal 27 days), compared to vancomycin-loaded scaffolds (bacteriostatic and bactericidal 14 days). The dual- and amikacin-loaded scaffolds were effective against P. aeruginosa, but eluates exhibited very short antibacterial properties; only 24 hours bacteriostatic and 1-5 hours bactericidal activity. For all groups, vancomycin recovery was near 100% whereas the amikacin recovery was 41%. In conclusion, in the presence of chitosan-nHA microspheres, the dual-antibiotic loaded scaffold was able to sustain an extended vancomycin elution longer than individually loaded scaffolds. The composite scaffold shows promise as a dual-drug delivery system for infected orthopaedic wounds and overcomes some deficits of other dual-delivery systems by extending the antibiotic release.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.1-19
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• 2020

In an underlay cognitive simultaneous wireless information and power transfer (SWIPT) network, communication from secondary user (SU) to secondary destination (SD) is accomplished with decode-and-forward (DF) relays. Multiple energy-constrained relays are assumed to harvest energy from SU via power splitting (PS) protocol and complete SU secure information transmission with beamforming. Hence, physical layer security (PLS) is investigated in cognitive SWIPT network. In order to interfere with eavesdropper and improve relay's energy efficiency, a destination-assisted jamming scheme is proposed. Namely, SD transmits artificial noise (AN) to interfere with eavesdropping, while jamming signal can also provide harvested energy to relays. Beamforming vector and power splitting ratio are jointly optimized with the objective of SU secrecy capacity maximization. We solve this non-convex optimization problem via a general two-stage procedure. Firstly, we obtain the optimal beamforming vector through semi-definite relaxation (SDR) method with a fixed power splitting ratio. Secondly, the best power splitting ratio can be obtained by one-dimensional search. We provide simulation results to verify the proposed solution. Simulation results show that the scheme achieves the maximum SD secrecy rate with appropriate selection of power splitting ratio, and the proposed scheme guarantees security in cognitive SWIPT networks.