• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.385-391
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• 2023

In the elderly population, sarcopenia occurs due to physical aging, leading to movement restrictions and loss of function. This results in dependence on daily activities and limitations in participation, ultimately decreasing the overall quality of life. In this study, we propose an algorithm designed to enable patients with sarcopenia to perform sit-to-stand and stand-to-sit movements seamlessly in their daily lives. The algorithm incorporates a wearable robot for muscle support and includes algorithms for standing and seated muscle strength support. To validate the algorithm's performance, EMG sensors were attached to the Rectus Femoris and Biceps Femoris muscles. The participants underwent two scenarios: one without wearing the device and one with the device providing muscle strength support, performing sit-to-stand and stand-to-sit motions for one minute in each case. The results showed a 16% increase in the EMG peak value of the Rectus Femoris muscle during standing motion (p=0.009). On the right side, there was a roughly 20% decrease (p=0.018) during standing and a 21% decrease (p=0.014) during sitting motion. In the future, we aim to gather additional data to further refine the algorithm. Our goal is to develop an optimal muscle strength support algorithm based on this data, making it applicable for real-life use by patients with sarcopenia.

• Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.392-409
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• 2024

The present study aims to analyze the biological aspects and population dynamics of Indian mackerel in Barru waters. Data was collected in Barru for 11 months, from June 2022 to April 2023. The observed parameters of biological aspects included gonadal maturation stages (GMSs), size at first gonadal maturation, and length-weight relationship. Meanwhile, the aspects of population dynamics encompass age group, growth, mortality rate, and exploitation rate. Data analysis consisted of morphological selection of general maturation stages, Spearman-Kärber method in estimating gonadal first maturation size, Bhattacharya method in identifying age group, von Bertalanffy function through FISAT II to measure growth (L_∞ and K), Pauly Model to estimate mortality rate, Beverton & Holt Model to estimate Y/R, and virtual population analysis (VPA) analysis to estimate stock and fish yield. The results demonstrated that GMS I was observed to be dominant, followed by stages II and III. The initial gonadal maturation was estimated to be 17.98-19.28 cm (FL) for females and 17.98-19.27 cm (FL) for males. The length-weight relationship in male and female Indian mackerels indicated a positive allometric growth. The mode grouping analysis results from the fork length measurement revealed three age groups. It was also identified that the asymptotic length (L_∞) = 29.5 cm (fork length), growth rate coefficient (K) = 0.46 per year, and theoretical age at zero length (t₀) = -0.3576 per year. Total mortality (Z) = 2.67 per year, natural mortality (M) = 1.10 per year, fishing mortality (F) = 1.57 per year, and exploitation rate (E) = 0.59, the actual Y/R = 0.083 gram/recruitment, and optimal Y/R 0.03 gram/recruitment. Fishing mortality is higher than the natural mortality rate, and a high exploitation value (E > 0.5) also reflects over-exploitation. VPA analysis on fish yields and stock estimation reported a highly exploited rate between the 11.5 cm and 14.5 cm length classes and an exceeding current yield of 467.07 tons/year with a recommended yield of 233.53 tons/year to ensure population sustainability.

• Journal of Environmental Policy
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• v.9 no.4
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• pp.3-27
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• 2010

In this paper, we have analyzed the cost structure of the Korean manufacturing industry in relation to the central government's environmental investment(CGEI below) by applying translog variable cost function. Important findings are as follows. First, sufficiency degree of CGEI of 0.7230, less than optimal level of 1, causes production inefficiency. Therefore, central government should forward a strategy to raise CGEI to meet appropriate standards. In addition, inspite of the deficiency of CGEI, shadow priceis lower than market price due to q-value of 0.9572, yielding unfavorable conditions for CGEI. However, CGEI brings about increase in output, variable cost saving, and economies of scale of firms. Second, by comparing this study with an existing study(2010), we have discovered the following facts. In both studies, we find that there are deficiency of investment, unfavorable conditions in investment, economies of scale, and output increase due to investment. However, the current study has found that, CGEI, which shows efficiency by positive(+) shadow price, saves variable cost. Therefore, firms suffer from production inefficiency due to variable cost caused by a shortage of efficient CGEI. Moreover, the previous study conducted in 2010 found that investment in prevention of environmental pollution(IPEP below), which indicates inefficiency by negative(-) shadow price, cannot reduce variable cost. In such circumstances, firms yield abnormal production efficiency based on variable cost savings caused by inefficient IPEP. For this reason, firms should raise IPEP to optimal level to reduce IPEP inefficiency to achieve production efficiency by reducing variable cost.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.163-167
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• 1995

New twenty 2-(n-octyl)-3-(n-propyl)isothiourea derivatives(S) were synthesized which is modified from the insecticidal Buprofezine (Applaud) in the selective insecticidal activities in-vitro against Diamond-Back moth (Plutella Xylostella Linnaeus). The structure activity relationships(SAR) between the insecticidal activity$(pI_{50})$ and a various physicochemical parameters of the substituent(Z) of S were analyzed by the multiple regression technique. The activities would depend largely on the MR, ${\pi}$ and $L_1$ parameters. The SAR was rationalized by parabolic function of MR, ${\pi}$ and $L_1$ constant, where the optimal values of the constants were $L_1=5.22{{\AA}}$, $MR=15.70\;Cm^3/mol$ and ${\pi}=1.60$, respectively. The steric effects play an important role in determining insecticidal activity. The SAR suggest that the S derivatives having a substituents with a small breadth and an appropriate length as Z group showed potent activity. From the results, the iso-propyl group(Z) substituent (5) with three carbon atom was the most effective compound.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.199-203
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• 2004

The gas response to a proposed spiral stellar pattern for our Galaxy is presented here as calculated via 2D hydrodynamic calculations utilizing the ZEUS code in the disk plane. The locus is that found by Drimmel (2000) from emission profiles in the K band and at 240 ${\mu}m$. The self-consistency of the stellar spiral pattern was studied in previous work (see Martos et al. 2004). It is a sensitive function of the pattern rotation speed, $\Omega$p, among other parameters which include the mass in the spiral and its pitch angle. Here we further discuss the complex gaseous response found there for plausible values of $\Omega$p in our Galaxy, and argue that its value must be close to $20 km s^{-l}\;kpc^{-1}$ from the strong self-consistency criterion and other recent, independent studies which depend on such parameter. However, other values of $\Omega$p that have been used in the literature are explored to study the gas response to the stellar (K band) 2-armed pattern. For our best fit values, the gaseous response to the 2-armed pattern displayed in the K band is a four-armed pattern with complex features in the interarm regions. This response resembles the optical arms observed in the Milky Way and other galaxies with the smooth underlying two-armed pattern of the old stellar disk populations in our interpretation. The complex gaseous response appears to be related to resonances in stellar orbits. Among them, the 4:1 resonance is paramount for the axisymmetric Galactic model employed, and the set of parameters explored. In the regime seemingly proper to our Galaxy, the spiral forcing appears to be marginally strong in the sense that the 4:1 resonance terminates the stellar pattern, despite its relatively low amplitude. In current work underway, the response for low values of $\Omega$p tends to remove most of the rich structure found for the optimal self-consistent model and the gaseous pattern is ring-like. For higher values than the optimal, more features and a multi-arm structure appears.

• Asia Marketing Journal
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• v.16 no.1
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• pp.35-69
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• 2014

The impact of competition on pricing has been studied in the context of counterfactual merger analyses where expected optimal prices in a hypothetical monopoly are compared with observed prices in an oligopolistic market. Such analyses would typically assume static decision making by consumers and firms and thus have been applied mostly to data obtained from consumer packed goods such as cereal and soft drinks. However such static modeling approach is not suitable when decision makers are forward looking. When it comes to the markets for durable products with indirect network effects, consumer purchase decisions and firm pricing decisions are inherently dynamic as they take into account future states when making purchase and pricing decisions. Researchers need to take into account the dynamic aspects of decision making both in the consumer side and in the supplier side for such markets. Firms in a two-sided market typically subsidize one side of the market to exploit the indirect network effect. Such pricing behaviors would be more prevalent in competitive markets where firms would try to win over the battle for standard. While such qualitative expectation on the relationship between pricing behaviors and competitive structures could be easily formed, little empirical studies have measured the extent to which the distinct pricing structure in two-sided markets depends on the competitive structure of the market. This paper develops an empirical model to measure the impact of competition on optimal pricing of durable products under indirect network effects. In order to measure the impact of exogenously determined competition among firms on pricing, we compare the equilibrium prices in the observed oligopoly market to those in a hypothetical monopoly market. In computing the equilibrium prices, we account for the forward looking behaviors of consumers and supplier. We first estimate a demand function that accounts for consumers' forward-looking behaviors and indirect network effects. And then, for the supply side, the pricing equation is obtained as an outcome of the Markov Perfect Nash Equilibrium in pricing. In doing so, we utilize numerical dynamic programming techniques. We apply our model to a data set obtained from the U.S. video game console market. The video game console market is considered a prototypical case of two-sided markets in which the platform typically subsidizes one side of market to expand the installed base anticipating larger revenues in the other side of market resulting from the expanded installed base. The data consist of monthly observations of price, hardware unit sales and the number of compatible software titles for Sony PlayStation and Nintendo 64 from September 1996 to August 2002. Sony PlayStation was released to the market a year before Nintendo 64 was launched. We compute the expected equilibrium price path for Nintendo 64 and Playstation for both oligopoly and for monopoly. Our analysis reveals that the price level differs significantly between two competition structures. The merged monopoly is expected to set prices higher by 14.8% for Sony PlayStation and 21.8% for Nintendo 64 on average than the independent firms in an oligopoly would do. And such removal of competition would result in a reduction in consumer value by 43.1%. Higher prices are expected for the hypothetical monopoly because the merged firm does not need to engage in the battle for industry standard. This result is attributed to the distinct property of a two-sided market that competing firms tend to set low prices particularly at the initial period to attract consumers at the introductory stage and to reinforce their own networks and eventually finally to dominate the market.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.2
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• pp.258-272
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• 1998

This investigation evaluated patients who received Steri-Oss implants from the Dental Hospital of Chosun University during the period from March 1989 to August 1997. 346 fixtures of 127 patients were included in this study. The results were as follows ; 1.The follow-up period was defined as the period between the surgical placement of the implants and the last follow-up examination. The mean follow-up period was $2.17{\pm}1.21$ years. 2.The period between fixture installation and second surgery was $0.71{\pm}0.44$ years in the maxilla and $0.46{\pm}0.21$ years in the mandible. 3.The number of fixtures which were installed in the upper jaw(112) was less than that in the lower jaw(234) and in the posterior region(260) was more than in the anterior region(86). 4.The length of fixture which was most frequently used was 12 mm and least was 8mm. Screw implants were installed more than cylindrical implants. 3.8mm implant was the most common implans, followed by 4.5mm and 3.25mm. 5.The number of augmentation cases was more than that of non-augmentation cases and the rate of augmentation cases in the maxilla was more than that in the mandible. 6.Implant restorations for partial edentulos patients(94cases) were more than single- tooth implant restorations(33cases) or implant restorations for complete edentulos patients(10cases). 7.Free-standing prostheses for partially edentulous patients were more commom than any other type of connection between implants and natural teeth. 8.Plaque Index($0.95{\pm}0.74$) and Gingival Index($0.31{\pm}0.52$) were very similar around the natural teeth and reflected an acceptable level of plaque and gingivitis control. Mean value for keratinized mucosa index($1.93{\pm}1.20$) remained fairly constant around level 2(1-2 mm keratinized epithelium). 9.Patients were generally satisfied with implant in terms of comfort, function, speech and esthetics. 10.There was not a statistically significant differences in overall survial rate between implants placed in the maxilla (91.5%) and those placed in the mandible (93.8%). Fourteen implants lost before the prosthetic rehabilitation and eleven implants lost following variable periods in function after the prosthetic phase of the treatment. 11.Cause of implant failures was exfoliation or removal of fixture due to non-osseointegration before the prosthetic rehabilitation or due to fracture of fixture, masticatory pain after the prosthetic rehabilitation. 12.The survival rate of Steri-Oss implants using the Kaplan-Meier statistical analysis was 93.8% at 2 year and 86.6% at 5 year, In all cases, implant losses occured predominantly in the healing period. There was a steep decline in the rate of implant loss after the first year. 13.The survival rate of Steri-Oss implants in the anterior region was 94.8% at 2 year and 94.8% at 5 year and that in the posterior region was 92.8% at 2 year and 75.9% at 5 year. In conclusion, this study revealed a number of parameters and guidelines for achieving an optimal success rate in osseointegration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.517-524
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• 2019

The overdrive hub clutch is attached to a 6-speed automatic transmission to reduce fuel consumption by using the additional power of the engine. This paper proposes a means to minimize the load and roll-over ratio on the punch during the piercing process for the overdrive hub clutch product. Die clearance, shear angle, and friction coefficient, which can affect the load and roll-over ratio of the punch during processing, were set as the design variables. Sensitivity analysis was also conducted to determine the influence of each design variable on the punch load and roll-over ratio. As a result, shear angle, friction coefficient and die clearance were found to be sensitive to load and roll-over ratio. The punch load and roll-over ratio were set as the objective function and the equation of each design variable and objective function was derives using the Response Surface Method. Finally, the optimal value of the design variables was derived using the Response Surface Method. Application of this model to finite element analysis resulted in 22.14% improvement in the roll-over ratio of the punch load and material.

• Journal of IKEEE
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• v.25 no.3
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• pp.493-500
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• 2021

In this paper, we propose the development of deep learning structure to improve quality of polygonal containers. The deep learning structure consists of a convolution layer, a bottleneck layer, a fully connect layer, and a softmax layer. The convolution layer is a layer that obtains a feature image by performing a convolution 3x3 operation on the input image or the feature image of the previous layer with several feature filters. The bottleneck layer selects only the optimal features among the features on the feature image extracted through the convolution layer, reduces the channel to a convolution 1x1 ReLU, and performs a convolution 3x3 ReLU. The global average pooling operation performed after going through the bottleneck layer reduces the size of the feature image by selecting only the optimal features among the features of the feature image extracted through the convolution layer. The fully connect layer outputs the output data through 6 fully connect layers. The softmax layer multiplies and multiplies the value between the value of the input layer node and the target node to be calculated, and converts it into a value between 0 and 1 through an activation function. After the learning is completed, the recognition process classifies non-circular glass bottles by performing image acquisition using a camera, measuring position detection, and non-circular glass bottle classification using deep learning as in the learning process. In order to evaluate the performance of the deep learning structure to improve quality of polygonal containers, as a result of an experiment at an authorized testing institute, it was calculated to be at the same level as the world's highest level with 99% good/defective discrimination accuracy. Inspection time averaged 1.7 seconds, which was calculated within the operating time standards of production processes using non-circular machine vision systems. Therefore, the effectiveness of the performance of the deep learning structure to improve quality of polygonal containers proposed in this paper was proven.

• Journal of Dental Rehabilitation and Applied Science
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• v.21 no.2
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• pp.153-167
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• 2005

The purpose of this study was to compare the v-shape thread with the square shape thread of fixture in the view of stress distribution pattern using finite element stress analysis. The finite element model was designed with the parallel placement of two standard fixtures(4.0 mm diameter ${\times}$ 11.5 mm length) on the region of mandibular 1st and 2nd molars. Three dimensional finite element model was created with the components of the implant and surrounding bone. This study simulated loads of 200 N at the central fossa in a axial direction (load A), 200 N at the buccal offset load that is 2 mm apart from central fossa in a axial direction (load B), 200 N at the buccal offset load that was 4 mm apart from central fossa in a axial direction (load C). These forces of load A',B',C' were applied to a $15^{\circ}$ inward oblique direction at that same site with 200 N. Von Mises stress values were recorded and compared in the supporting bone, fixture, and abutment screw. The following results have been made based on this study : 1. The highest stress concentration occurred at the cervical region of the implant fixture. 2. Von Mises stress value of off-site region was higher than that of central fossa region. 3. Square shape thread type showed more even stress distribution in the vertical and oblique force than V-shape thread type. 4. Stress distribution was the most effective in the case of buccal offset load (2, 4 mm distance from central fossa) in the square shape thread type. 5. V-shape thread type revealed higher von Mises stress value than square shape thread type in all environmental condition. The results from numerical analyses concluded that square shape thread type had the lower destructive stress and more stress distribution between the fixture and bone interface than V-shape thread type. Therefore, square shape thread type was regarded as optimal thread configuration in biomechanical concepts.