• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.9
• /
• pp.4327-4330
• /
• 2012

The mouse double minute 2 (MDM2) gene plays a key role in the p53 pathway, and the SNP 309T/G single-nucleotide polymorphism in the promoter region of MDM2 has been shown to be associated with increased risk of cancer. However, no consistent results were found concerning the relationships between the polymorphism and prostate cancer risk. This meta-analysis, covering 4 independent case-control studies, was conducted to better understand the association between MDM2-SNP T309G and prostate cancer risk focusing on overall and subgroup aspects. The analysis revealed, no matter what kind of genetic model was used, no significant association between MDM2-SNP T309G and prostate cancer risk in overall analysis (GT/TT: OR = 0.84, 95%CI = 0.60-1.19; GG/TT: OR = 0.69, 95%CI = 0.43-1.11; dominant model: OR = 0.81, 95%CI= 0.58-1.13; recessive model: OR = 1.23, 95%CI = 0.95-1.59). In subgroup analysis, the polymorphism seemed more likely to be a protective factor in Europeans (GG/TT: OR = 0.52, 95%CI = 0.31-0.87; recessive model: OR = 0.58, 95%CI = 0.36-0.95) than in Asian populations, and a protective effect of the polymorphism was also seen in hospital-based studies in all models (GT/TT: OR = 0.74, 95%CI = 0.57-0.97; GG/TT: OR = 0.55, 95%CI = 0.38-0.79; dominant model: OR = 0.69, 95%CI = 0.54-0.89; recessive model: OR = 0.70, 95%CI = 0.51-0.97). However, more primary studies with a larger number of samples are required to confirm our findings.

• Journal of Korean Institute of Industrial Engineers
• /
• v.26 no.2
• /
• pp.81-87
• /
• 2000

As for M/G/1 queueing system, we use various control policies, with which we can optimize the system. Up to now the most widely adopted policies are N-Policy, T-Policy, D-Policy, and so on. The existing researches are largely concerned to find an optimal operation condition or to optimize the system under single policy in M/G/1 system. There are, however, few literatures dealing with multiple control policies at once to enhance the flexibility of the model. In this study, we consider M/G/1 system adopting N-Policy and T-Policy simultaneously. If one of two conditions is satisfied, then, the server starts the service. We call this Min(N,T)-Policy. We find the probability distribution of the number of customers and mean waiting time in steady state and derive a cost function. Next, we seek the $N^*$, optimal threshold under various N values. Finally, we reveal the characteristics of cost function.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.860-879
• /
• 2002

Traditionally, Geographical Information Systems can only process spatial data in a procedure-oriented way, and the data can't be treated integrally. This method limits the development of spatial data applications. A new and promising method to solve this problem is the spatial structural query language, which extends SQL and provides integrated accessing to spatial data. In this paper, the theory of spatial structural query language is discussed, and a new geographical data model based on the concepts and data model in OGIS is introduced. According to this model, we implemented a spatial structural query language G/SQL. Through the studies of the 9-Intersection Model, G/SQL provides a set of topological relational predicates and spatial functions for GIS application development. We have successfully developed a Web-based GIS system-WebGIS-using G/SQL. Experiences show that the spatial operators G/SQL offered are complete and easy-to-use. The BNF representation of G/SQL syntax is included in this paper.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.3
• /
• pp.250-256
• /
• 2000

The purpose of this study was to investigate the adsorption kinetics of heavy metals (Cu, Cd and Pb) using three tidal flat sediments and two yellow loesses. The relationship between adsorption rate calculated by non-linear regression model and chemical parameters was estimated. The contents of ignitiot loss (I.L.) am Fe, Mn and Al oxides of yellow loess were higher $1.5{\~}6 times$ than those of tidal flat sediments. But the contents of silt and clay of tidal flat sediment in Eueunri was higher than others. Heavy metals adsorption were occured rapidly in the intial 30 min and the concentration of adsorbed heavy metals were $4.1{\~}14.7\;{\mu}g/g\;for\;Cu,\;2.8{\~}16.7\;{\mu}g/g\;for\;Cd\;and\;43.4{\~}101.7\;{\mu}g/g$ for Pb, showing a high cumulative adsorption of $8{\~}70{\%}\;for\;Cu,\;18{\~}31{\%}\;for\;Cd and\;19{\~}52{\%}$ for Pb after 3hr. In initial concentration of $0.5{\times}10^(-5)M$, adsorption rate of heavy metals by the tidal flat sediments and yellow loesses was the sequence Pb>Cu^gt;Cd. The adsorption kinetics of Cu, Cd and Pb was found to be one-site kinetic model. Especially, in the case of Cu, there was a high negative ($R^2= -0.88{\~}-0.99$) linear correlation between chemical parameter such as I.L., Al oxide, silt and clay, and adsorption rate coefficients ($K_a$) calculated by non-linear model.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.11
• /
• pp.4203-4223
• /
• 2021

Accelerated by the Internet of Things (IoT), the need for further technical innovations and developments within wireless communications beyond the fifth generation (B5G) networks is up-and-coming in the past few years. High altitude platform station (HAPS) communication is expected to achieve such high levels that, with high data transfer rates and low latency, millions of devices and applications can work seamlessly. The HAPS has emerged as an indispensable component of next-generations of wireless networks, which will therefore play an important role in promoting massive IoT interconnectivity with 6G. The performance of communication and key technology mainly depend on the characteristic of channel, thus we propose an efficient Markov chain based channel model, then analyze the HAPS communication system's uplink capability and swing effect through experiments. According to the simulation results, the efficacy of the proposed scheme is proven to meet the requirements of ubiquitous connectivity in future IoT enabled by 6G.

• Communications for Statistical Applications and Methods
• /
• v.12 no.3
• /
• pp.545-556
• /
• 2005

Hjort(1990) obtained the nonparametric Bayes estimator $\^{F}_{c,a}$ of $F_0$ with respect to beta processes in the random censorship model. Let $X_1,{\cdots},X_n$ be i.i.d. $F_0$ and let $C_1,{\cdot},\;C_n$ be i.i.d. G. Assume that $F_0$ and G are continuous. This paper shows that {$\^{F}_{c,a}$(u){\|}0 < u < T} converges weakly to a Gaussian process whenever T < $\infty$ and $\~{F}_0({\tau})\;<\;1$.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.5
• /
• pp.474-481
• /
• 2009

Fracture models and criteria of adhesive with two parameters, namely $G_C$ and ${\sigma}_{max}$, have been developed to describe the fracture process of adhesive joints. Cohesive zone model(CZM) is a representative two parameter failure criteria approach. In CZM, ${\sigma}_{max}$ is a critical, limiting maximum value of the stress in the damage zone ahead of the crack and is assumed to have some physical significance in adhesive failure. Based on CZM and finite element analysis method, the relationship between fracture load and adhesive properties, as $G_{IC)$ and $({\sigma}_{max})_I$, was investigated in adhesively bonded joint tensile test and T-peel test. The two parameters in tensile mode loading were evaluated by using the relationship. The value of $G_{\IC}$ evaluated by proposed method showed close agreement with analytical solution for tapered double cantilever beam(TDCB) test which proposed in an ASTM standard.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.7 no.5
• /
• pp.139-150
• /
• 2007

As computer technology has been rapidly advanced, geographic information system (GIS) is recently used in many disciplines. In this study, for a model area in Seoul, seismic hazard potential relating to site effects, which are influenced by the subsurface geotechnical conditions, was estimated using the GIS tool. The distribution of pre-existing borehole drilling data in Seoul metropolitan area was examined for the regional estimation of site-specific seismic responses at the model area. Spatial geo-layers across the entire model area were predicted by constructing a GIS-based geotechnical information system (GTIS). A microzonation of site period $(T_G)$ for estimating site-specific seismic responses at the model area was performed within the GTIS. The spatial microzoning map of $T_G$ indicated seismic vulnerability of two- to four-storied buildings in the model area. Furthermore, a site classification map for determining the design ground motion was established based on the $T_G$ within the GTIS. This informed that most of location in the model area was categorized into current site classes C and D. This seismic microzonation framework for the model area could be applicable particularly in the entire Seoul metropolitan area based on the pre-existing borehole data.

• Journal of the Korean Mathematical Society
• /
• v.45 no.6
• /
• pp.1753-1767
• /
• 2008

Consider the nonparametric regression model $Y_{ni}\;=\;g(x_{ni})+{\epsilon}_{ni}$ ($1\;{\leq}\;i\;{\leq}\;n$), where g($\cdot$) is an unknown regression function, $x_{ni}$ are known fixed design points, and the correlated errors {${\epsilon}_{ni}$, $1\;{\leq}\;i\;{\leq}\;n$} have the same distribution as {$V_i$, $1\;{\leq}\;i\;{\leq}\;n$}, here $V_t\;=\;{\sum}^{\infty}_{j=-{\infty}}\;{\psi}_je_{t-j}$ with ${\sum}^{\infty}_{j=-{\infty}}\;|{\psi}_j|$ < $\infty$ and {$e_t$} are negatively associated random variables. Under appropriate conditions, we derive a Berry-Esseen type bound for the estimator of g($\cdot$). As corollary, by choice of the weights, the Berry-Esseen type bound can attain O($n^{-1/4}({\log}\;n)^{3/4}$).

• Geomechanics and Engineering
• /
• v.29 no.6
• /
• pp.615-626
• /
• 2022

The soft clays are widely distributed, and one of the prominent engineering problems is the creep behavior. In order to predict the creep deformation of soft clays in an easier and more acceptable way, a simple creep constitutive model has been proposed in this paper. Firstly, the triaxial creep test data indicated that, the strain-time (𝜀-t) curve showing in the 𝜀-lgt space can be divided into two lines with different slopes, and the time referring to the demarcation point is named as t_EOP. Thereafter, the strain increments occurred after the time t_EOP are totally assumed to be the creep components, and the elastic and plastic strains had occurred before t_EOP. A hyperbolic equation expressing the relationship between creep volumetric strain, stress and time is proposed, with several triaxial creep test data of soft clays verifying the applicability. Additionally, the creep flow law is suggested to be similar with the plastic flow law of the modified Cam-Clay model, and the proposed volumetric strain equation is used to deduced the scaling factor for creep strains. Therefore, a creep constitutive model is thereby established, and verified by successfully predicting the creep principal strains of triaxial specimens.