• Journal of the Korean housing association
• /
• v.18 no.6
• /
• pp.45-55
• /
• 2007

The study is based on a two-year research study titled 'A study on the Development of the Programs for Housing Policy to support Multi-family Housing Remodeling in Korea'. The primary purpose of this two-year study was to recommend governmental program initiatives for supporting multi-family housing remodeling activities in Korea. As a part of this research study, this article was written based on the results from the two surveys regarding multi-family housing remodeling in the United States and Korea, and a focus group with housing researchers affiliated to the Joint Center for Housing Studies. Major research findings are presented as follows: First, there have been various types of supportive programs for single- and multi-family housing remodeling in the United States. Those have focused on lower income families than middle income families. Compared with the programs in the United States, the apartment remodeling in Korea has been focusing on small population of the multi-family housing owners. Apartment remodeling in Korea needs supportive programs for rental housing remodeling and the housing remodeling for low-incomes. Second, there have been various types of remodeling activities made in multi-family housing properties in the United States. Size of remodeling project also varied. Their remodeling activities were based on the long-term repairing plans initiated by professional apartment management groups. For making our multi-family housing properties more sustainable, we also need to have the long-term repairing plans. Third, the apartment property remodeling has been regarded as a substitute of reconstruction of apartment properties. However, remodeling should be regarded as one of the most efficient ways to extend the life-cycle of apartment buildings. Thus, benefits and executive plans of apartment remodeling should be studied by a professional research center under our governmental responsibilities as done in the United States.

• Journal of KIISE:Information Networking
• /
• v.30 no.1
• /
• pp.17-23
• /
• 2003

In this Paper. we Propose a digital watermarking scheme for digital images based on a perceptual model, the frequency masking, texture making, and luminance masking Properties of the human visual system(HVS), which have been developed in the context of image compression. We embed two types of watermark, one is pseudo random(PN) sequences, the other is a logo image. To embed the watermarks, original images are decomposed into $8\times8$ blocks, and the discrete cosine transform(DCT) is carried out for each block. Watermarks are casted in the low frequency components of DCT coefficients. The perceptual model adjusts adaptively scaling factors embedding watermarks according to the local image properties. Experimental results show that the proposed scheme presents better results than that of non-perceptual watermarking methods for image qualify without loss of robustness.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.4
• /
• pp.399-415
• /
• 2014

The aim of this study was to investigate the effect of resistance training with and without whole-body vibration(WBV) on the biomechanical properties of the plantarflexor in the elderly women (>60 yrs., n=35). Thirty-five volunteers were randomly assigned to a resistance training with WBV group (RVT, n=14), a resistance training without WBV (RT, n=11), and a non-training control group (CON, n=10). The RVT and the RT groups participated in the training sessions three times a week for 8 weeks, followed by a 4-week detraining period. The CON group was instructed to refrain from any type of resistance training. To assess strength and activation of the plantarflexor muscles, maximum isometric ankle plantarflexion torque and muscle activation of the triceps surae muscles were measured using dynamometry, twitch interpolation technique and electromyography at four different ankle joint angles. Also, the lower extremity function was assessed by vertical jumping. The measurements were performed prior to, 2 and 8 weeks after the training and after a 4-week detraining period. Following the 8-week training sessions, an increase in the isometric plantarflexion strength was found to be greater for the RVT compared with the RT group (p<.05). Muscle inhibition was significantly decreased after training than before training only for the RVT (p<.05). Following the detraining period, a decrease in isometric plantarflexors strength and a increases in muscle inhibition were significantly less in the RVT compared with the RT group. In conclusion, the exercise with WBV is a feasible training modality for the elderly and seems to have a boosting effect when used with conventional resistance training.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.2 no.1
• /
• pp.79-93
• /
• 1998

The eigenvalue problem is presented for the building with added viscoelastic dampers by using component mode method. The Lagrange multiplier formulation is used to derive the eigenvalue problem which is expressed with the natural frequencies of the building, the mode components at which the dampers are added, and the viscoelastic property of the damper. The derived eigenvalue problem has a nonstandard form for determining the eigenvalues. Therefore, the problem is examined by the graphical depiction to give new insight into the eigenvalues for the building with added viscoelastic dampers. Using the present approach the exact eigenvalues can be found and also upper and lower bounds of the eigenvalues can be obtained.

• The Korean Journal of Applied Statistics
• /
• v.34 no.4
• /
• pp.537-556
• /
• 2021

Properties of statistical process control procedures may not be derived analytically in many cases; however, the application of a Markov chain can solve such problems. This article shows how to derive the properties of the process control procedures using the generated Markov chains when the control statistic satisfies the Markov property. Markov chain approaches that appear in the literature (such as the statistical design and economic design of the control chart as well as the variable sampling rate design) are reviewed along with the introduction of research results for application to a new control procedure and reset chart. The joint application of a Markov chain approach and analytical solutions (when available) can guarantee the correct derivation of the properties. A Markov chain approach is recommended over simulation studies due to its precise derivation of properties and short calculation times.

• Composites Research
• /
• v.33 no.6
• /
• pp.401-407
• /
• 2020

At the engineering and industrial areas, the lightweight composite material has been substituted with the metals, such as steel at the structural parts. This composite material has been applied by the adhesive bonding method, as well as the joint methods with rivets, welds or bolts and nuts. The study on the strength characteristics of adhesive interface is necessarily required in order to apply the method to composite materials. CFRP specimens as the fiber reinforced plastic composites were manufactured easily and this study was carried out. The static experiments were performed under the loading conditions of in-plane and out-plane shears with the inhomogeneous composite TDCB specimens with CFRP, aluminum (Al6061), and aluminum foam (Al-foam). Through the result of this study, the durability on the inhomogeneous composite structure with adhesive interface was investigated by examining the fracture characteristic and the point in time.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.3
• /
• pp.21-30
• /
• 2021

Architectural cultural properties suffer a lot of damage due to various environmental factors. In order to preserve damaged cultural properties, preventive preservation and long-term preservation management are becoming more important. Therefore, research on a scientific non-destructive testing method applicable to regular inspection is required. For related research, DangGan with a high flag-pole shape was selected as the subject of study among various cultural properties. Among the preserved DangGans, a basic study was conducted on the analysis technique to evaluate the structural stability by selecting Treasure No. 49 Naju SeokDangGan. An idealized model was presented and a multi-degree of freedom equation of motion was derived. In addition, an equation for estimating the critical stiffness value for each joint position is presented.

• Korean Journal of Plant Resources
• /
• v.34 no.6
• /
• pp.555-565
• /
• 2021

Melon fruits are a year-old plant in the family Cucurbitae and are the most cultivated fruit in tropical countries. Melon flesh is an important source of anti-cancer, antioxidant effects, attracting attention as a functional food. We investigated the morphological properties, β-carotene content, and cucumisin activity of seeds of 58 melon genetic resources. Melon resources have shown various morphological properties. Melons grouped by morphological properties were the five groups. β-carotene content varied between 82.34 mg/kg, 86.75 mg/kg, 25.56 mg/kg, 86.25 mg/kg, and 54.65 mg/kg. Between β-carotene, cucumisin activity and other quantitative fruit morphological properties, the color of the pulp and the firmness of the pulp had a significant amount of correlation between the β-carotene content. However, cucumisin activity and β-carotene content had significant negative correlation, and the color of the fruit and shape of the fruit had significant negative correlation with β-carotene content and activity of cucumisin. Our study vindicated that high diversity in melon morphological characters of genetic sources that provide beneficial baseline data for the future and in the activity of β-carotene and cucumisin, and these results could predict indicators of β-carotene content by the length of leaf, the width of fruit, the length of joint, and the length of seed, and collectively the morphological properties of melons could help predict indicators of β-carotene content and help develop functional sarcoma and farmhouse cultivation.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.443-449
• /
• 2022

With climate change and the global population growth, the frequency and scope of wildfires are constantly increasing, which threatened people's lives and property. For example, according to California Department of Forestry and Fire Protection, in 2020, a total of 9,917 incidents related to wildfires were reported in California, with an estimated burned area of 4,257,863 acres, resulting in 33 fatalities and 10,488 structures damaged or destroyed. At the same time, the ongoing development of technology provides new tools to simulate and analyze the spread of wildfires. How to use new technology to reduce the losses caused by wildfire is an important research topic. A potentially feasible strategy is to simulate and analyze the spread of wildfires through computing technology to explore the impact of different factors (such as weather, terrain, etc.) on the spread of wildfires, figure out how to take preemptive/responsive measures to minimize potential losses caused by wildfires, and as a result achieve better management support of wildfires. In preparation for pursuing these goals, the authors used a powerful computing framework, Spark, developed by the Commonwealth Scientific and Industrial Research Organization (CSIRO), to study the effects of different weather factors (wind speed, wind direction, air temperature, and relative humidity) on the spread of wildfires. The test results showed that wind is a key factor in determining the spread of wildfires. A stable weather condition (stable wind and air conditions) is beneficial to limit the spread of wildfires. Joint consideration of weather factors and environmental obstacles can help limit the threat of wildfires.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.1
• /
• pp.27-35
• /
• 2015

The material properties of crack growth models at an elevated temperature were derived from the results of numerous crack growth tests for Mod.9Cr-1Mo (ASME Grade 91) steel specimens under fatigue loading and creep loading at an elevated temperature. These crack growth models were needed for defect assessment under creep-fatigue loading. The mathematical crack growth rate models for fatigue crack growth (FCG) and creep crack growth (CCG) were determined based on the test results, and the models were compared with those of the French design code RCC-MRx to investigate the conservatism of the code. The French design code RCC-MRx provides an FCG model and a CCG model for Grade 91 steel in Section III Tome 6. It was shown that the FCG model of RCC-MRx is conservative, while the CCG model is non-conservative compared with the present test data. Thus, it was shown that further validation of the property was required. Mechanical strength tests and creep tests were also conducted, and the test results were compared with those of RCC-MRx.