• Journal of Korean Tunnelling and Underground Space Association
• /
• v.8 no.3
• /
• pp.249-257
• /
• 2006

The spatial distribution of design parameters greatly affects tunnel behavior during and after construction, as well as in the long-term temporal responses. However, the tunnel design parameters commonly used in numerical modeling tend to be representative or average values of global-scale properties. Furthermore, the uncertainty and spatial variation of the design parameters increase as the tunnel scale increases. Consequently, the probability of failure also increases. In order to achieve structural stability in large-section tunnels, the design framework must take into consideration the quantitative effect of design parameter variations on tunnel behavior. Therefore, this paper suggests a statistical approach to numerical modeling to explore the effect of spatially distributed design parameters in a circular tunnel. Also, the effect of spatial variation in the lining strength is studied in this paper. The numerical results suggest that the deformation around the tunnel increases with an increase in the variation of the design parameters.

• Applied Chemistry for Engineering
• /
• v.30 no.6
• /
• pp.737-741
• /
• 2019

A low-cost and flexible potassium ion (K⁺) sensor was fabricated through a screen-printed process. Uniform and conformal coating of conductive inks was verified by scanning electron microscopy and optical microscopy measurements. The K⁺-sensors showed a high sensitivity, fast response time, and low detection limit. The sensitivity of K⁺-sensor was similar to that of both mechanically normal and bent states. The K⁺-sensor exhibited a good reproducibility with no hysteresis effect and excellent long term stability. In addition, the K⁺-sensor showed an excellent selectivity for K⁺ concentrations in the presence of other interfering cation ions. Successful measurements of K⁺ concentrations in sports drink samples were demonstrated by comparing K⁺ concentration values from K⁺-sensor to those of using a commercial K⁺-meter.

• Journal of Oral Medicine and Pain
• /
• v.36 no.1
• /
• pp.65-70
• /
• 2011

The purpose of this study is introduce the spiral taping treatment on Temporomandibular Disorder in oral Medicine. The taping treatment is relatively simple and dosen't have any adverse effect, so it has high stability and superior effect of treatment. In this study, using the spiral taping treatment as one of the effective taping treatments, non-stretched tape was attatched to the muscles which set limit to the range of joint movement and cause pain to temporomandibular joint. With that treatment this study tried to make effective results of treatment of temporomandibular disorder. These results suggest spiral taping treatments contribute to the improvement of tempermandibular disorders. Further this study is needed for the confirmation of this effect of spiral taping treatments on temporomandibular disorders.

• Analytical Science and Technology
• /
• v.23 no.4
• /
• pp.331-346
• /
• 2010

Perfluorinated compounds have characteristics of resistance to heat, acidic, basic conditions and also resist water, oil, grease, pollutant. Futhermore they are used by various industrial material, nowadays, they produced in large scale for indutrial and commercial areas. However, they also resist metabolizing and degrading in environmental system (plant, animal, even human body). Moreover, in animal's bodies, PFCs can be accumulated in organ (eg; liver) and lead to liver cell necrosis even oncogenesis. Perfluorinated compounds are newly registered as new persistent organic pollutants (POPs) on Stockholm convention in 2009. Therefore necessity for analytical methodology for determination of PFCs in various environmental samples is even more increased. This study discussed sample preparation and instrumental conditions for the analysis of PFCs in environmental and biota samples.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.17 no.1
• /
• pp.139-144
• /
• 2007

A broadcast authentication is important and fundamental consideration for security in wireless sensor networks. Perigg et al suggests ${\mu}-TESLA$ used a key chain. But it is unavoidable the delay of time to authenticate packets. so it is hard to meet the property that most application of sensor are performed in real-time. To cope with these problems we propose an efficient broadcast authentication scheme which has no delay of time and provides re-keying mechanism. we also describe an analysis of security and efficiency for this scheme.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.16 no.2
• /
• pp.135-148
• /
• 2014

This study was performed to evaluate the performance about Improved C12A7 based mineral accelerator (ICM) increased in initial and long-term strength. ICM was developed to overcome the long-term strength decrease in existing accelerator. To evaluate the performance of ICM according to addition rate, setting time, compressive strength, and flexural strength tests were conducted in laboratory. In results, initial setting time was slower, final setting time was faster than existing $C_{12}A_7$ based mineral accelerator (CM) when usage of ICM 6%. In compressive and flexural strength, existing CM was higher than ICM at 3hours and 1day. After 7days, strength of shotcrete using ICM was increased. Rebound test, compressive strength and flexural strength test with optimum addition rate through the laboratory test were conducted in field. Field experiment results were the same as laboratory test. Long-term strength performance of ICM was superior to existing accelerator.

• 한국노년학
• /
• v.37 no.3
• /
• pp.617-635
• /
• 2017

The aim of this study was to investigate both poverty and depression among older adults, focusing on the relationship of these two trajectories. For expanding the understanding about elderly poverty and depression, the study measured the longitudinal patterns of various transition in these two variables. The data for the study is 1st to 9th waves (2006-2014) of Korea Welfare Panel Study (KoWePS), and 4,431 older adults were used for the final analysis. For data analysis, Semi-parametric group-based modeling and Dual trajectory model were selected. The main results of this study were followings; First, The trajectory groups were identified: non-poverty, decrease poverty, increase poverty, remain high-poverty, chronic poverty groups and 4 trajectories of depression: stable, remain low-depression, risk of depression, chronic depression groups. Second, the study was tried to anticipate the longitudinal transition of poverty and depression status, and investigate the concurrent relationship in these two variables. It turned out that the stable poverty status led the stable depression, and vice versa. Based on these result, this study for elderly welfare were discussed to reduce risk for poverty and depression.

• Land and Housing Review
• /
• v.6 no.4
• /
• pp.195-213
• /
• 2015

Recently, there has been changing the housing rental market paradigm structure which has been increased the ratios of partly monthly rental ratios, because of increasing chonsei's price, the preference of monthly rental and the rack of chonsei's supply amount. This study had done a survey of 1,400 people for private and public rental residents by region and housing types during Dec. 2014. According to the result of survey, Market participant prospect strongly to change chonsei to monthly rental market structure and the reason of rising of chonsei's price is the preference of householder's monthly rental because of decreasing interest rate and the rack of chonsei's supply amount. The housing policy's proposal of the stability of low income class's housing and jense's price strongly recommended the expansion of public rental housing supply and the activation of private rental housing, the expansion of chonsei loan, housing boucher etx. The rental market policy for high income class have desired to market autonomy than public side's intervention, on the other hands, the rental market policy for low income class have strongly need to the public side's intervention such as the contiuneous long-term rental housing supply.

• Journal of Service Research and Studies
• /
• v.12 no.1
• /
• pp.49-68
• /
• 2022

This study was conducted to design a financial system for the sustainable life of mankind. Human society faces a constant crisis and leads a life while overcoming it. The polarization is intensifying in the process of overcoming the economic crisis or crisis caused by the virus. In a society adopting the capitalist economic system, it is a common phenomenon that polarization intensifies with the passage of time, but since the intensification of polarization can destroy human society as a community, active countermeasures are required. The purpose of this study was to prevent the deepening of polarization by redesigning important financial-related systems from the perspective of human life and maintenance of human society. Through the history of mankind, monetary and financial systems related to sustainable society have been analyzed, and a financial system model that is ideal for the modern and future society and is sustainable in the long term has been derived. The conditions for a long-term sustainable financial system should be a model that can solve the problems of the current system, such as deepening polarization, and a model that is faithful to the characteristics of the modern economic society and the essence of sustainable life. And it can be sustainable only if it is based on the common principles of human society. It should be a model that guarantees core values such as growth and equality that human society demands. After analyzing the problems of the current economic system and analyzing the conditions required for the new system, the basic axioms that the new financial system should be based on were presented, and a desirable model was derived based on this. The structure of the derived model and the specific operation model were presented. In the future, follow-up studies are needed to concrete this model.

• Journal of the Microelectronics and Packaging Society
• /
• v.10 no.4
• /
• pp.21-27
• /
• 2003

The copolymers with various composition of methyl methacrylate (MMA), ethyl methacrylate (EMA), methacrylic acid (MA) and hydroxyethyl methacrylate (HEMA) were synthesized for capacitive humidity sensitive materials. The capacitive humidity sensor consisted of a polymethacrylate film coated on both sides with gold electrode. Capacitance versus relative humidity increased with HEMA content in the copolymer. In the case of self-crosslinkable MMA/MA/HEHA= 40/10/10, the average capacitance at 30%RH, 60%RH and 90%RH are 102, 134 and 166 pF, respectively. And also, the hysteresis, temperature cycle and long-term stability were evaluated as a capacitance humidity sensor.