• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권4호
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• pp.1638-1654
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• 2018

The heterogeneous network (HetNet) has been one of the key technologies in Long Term Evolution-Advanced (LTE-A) with growing capacity and coverage demands. However, the introduction of femtocells has brought serious co-layer interference and cross-layer interference, which has been a major factor affecting system throughput. It is generally acknowledged that the resource allocation has significant impact on suppressing interference and improving the system performance. In this paper, we propose a hybrid-clustering algorithm based on the $Mat{\acute{e}}rn$ hard-core process (MHP) to restrain two kinds of co-channel interference in the HetNet. As the impracticality of the hexagonal grid model and the homogeneous Poisson point process model whose points distribute completely randomly to establish the system model. The HetNet model based on the MHP is adopted to satisfy the negative correlation distribution of base stations in this paper. Base on the system model, the spectrum sharing problem with restricted spectrum resources is further analyzed. On the basis of location information and the interference relation of base stations, a hybrid clustering method, which takes into accounts the fairness of two types of base stations is firstly proposed. Then, auction mechanism is discussed to achieve the spectrum sharing inside each cluster, avoiding the spectrum resource waste. Through combining the clustering theory and auction mechanism, the proposed novel algorithm can be applied to restrain the cross-layer interference and co-layer interference of HetNet, which has a high density of base stations. Simulation results show that spectral efficiency and system throughput increase to a certain degree.

• 열처리공학회지
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• 제31권6호
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• pp.269-274
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• 2018

Grain-oriented electrical steel sheets are mainly used as core materials for transformers and motors. They should have excellent magnetic properties such as low core loss, high magnetic flux density and high permeability. In order to improve the magnetic properties of the electrical steel sheet, it is important to form Goss oriented grains with a very strong {110}<001> orientation. Recently, efforts have been made to develop Goss grains by controlling processes such as hot rolling, cold rolling, and primary and secondary recrystallization. In this study, the sheets containing 3.2 and 3.4wt.% Si were used, which were rolled with 1 and 10 passes with total thickness reduction of 89%. Heating was carried out for primary recrystallization with different heating rates of $25^{\circ}C/s$ and $24^{\circ}C/min$ until $720^{\circ}C$. The behavior of Goss-, {411}<148>-, and {111}<112>-oriented grains were analyzed using X-ray diffraction(XRD) and electron back-scatter diffraction(EBSD) analysis. The area fraction of Goss-oriented grains increased with the number of rolling passes during cold rolling; however, after the primary recrystallization, the area fraction of the Goss grains was higher and exact Goss grains were found in the specimens subjected to rapid heating after one rolling pass.

• 한국미생물·생명공학회지
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• 제21권4호
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• pp.354-365
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• 1993

A novel control method with automatic tuning of PID controller parameters has been developed for efficient regulation of dissolved oxygen concentration in fed-batch fermentations of Escherichia coli. Agitation speed and oxygen partial pressure in the inlet gas stream were chosen to be the manipulated variables. A heuristic reasoning allowed improved tuning decisions from the supervision of control performance indices and it coule obviate the needs for process assumptions or disturbance patterns. The control input consisted of feedback and feedforword parts. The feedback part was determined by PID control and the feedforward part is determined from the feed rate. The proportional gain was updated on-line by a set of heuristics rules based on the supervision of three performance indices. These indices were output error covariance, the average value of output error, and input covariance, which were calculated on-line using a moving window. The integral and derivative time constants were determined from the period of output response. The specific growth rate was maintained at a low level to avoid acetic acid accumulation and thus to achieve a high cell density. The specific growthe rate was estimated from the carbon dioxide evolution rate. In fed-batch fermentation, the simutaneous control of dissolved oxygen concentration (at 0.2; fraction of saturated value) and specific growth rate (at 0.25$hr^{-1}$) was satisfactory for the entire culture period in spite of the changes in the feed rate and the switching of control input.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1995년도 제9회 식물생명공학 심포지움 식물육종과 분자생물학의 만남 The 9th Plant Biotechnology Symposium -Breeding and Molecular Biology-
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• pp.57-86
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• 1995

Molecular mapping of plant genomes has progressed rapidly since Bostein et al.(1980) introduced the idea of constructing linkage maps of human genome based on restriction fragment length polymorphism (RFLP) markers. In recent years, the development of protein and DNA markers has stimulated interest for the new approaches to plant improvement. While classical maps based on morphological mutant markers have provided important insights into the plant genetics and cytology, the molecular maps based on molecular markers have a number of inherent advatages over classical genetic maps for the applications in genetic studies and/or breeding schemes. Isozymes and DNA markers are numerous, discrete, non-deleterious, codominant, and almost entirely free of environmental and epistatic interactions. For these reasons, they are widely used in constructing detailed linkage maps in a number of plant species. Plant breeders improve crops by selecting plants with desirable phenotypes. However a plant's phenotyes is often under genetic control, positioning at different "quantitative trait loci" (QTLs) together with environmental effects. Molecular maps provide a possible way to determine the effect of the individual gene that combines to produce a quantitative trait because the segregation of a large number of markers can be followed in a single genetic cross. Using market-assisted selection, plants that contain several favorable genes for the trait and do not contain unfavourable segments can be obtained during early breeding processes. Providing molecular maps are available, valuable data relevant to the taxonomic relationships and chromosome evolution can be accumulated by comparative mapping and also the structural relationships between linkage map and physical map can be identified by cDNA sequencing. After constructing high density maps, it will be possible to clone genes, whose products are unknown, such as semidwarf and disease resistance genes. However, much attention has to be paid to level-up the basic knowledge of genetics, physiology, biochemistry, plant pathology, entomology, microbiology, and so on. It must also be kept in mind that scientists in various fields will have to make another take off by intensive cooperation together for early integration and utilization of these newly emerging high-techs in practical breeding. breeding.

• 한국분말재료학회지
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• 제18권2호
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• pp.149-158
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• 2011

Electro-Discharge Sintering (EDS) employs a high-voltage/high-current-density pulse of electrical energy, discharged from a capacitor bank, to instantaneously consolidate powders. In the present study, a single pulse of 0.57-1.1 kJ/0.45 g-atomized spherical $Ti_{52}Zr_{28}Ni_{20}$ powders in size range of 10~30 and $30\sim50{\mu}m$ consisting of ${\beta}$-(Ti, Zr) and icosahedral phases were applied to examine the structural evolution of icosahedral phase during EDS. Structural investigation reveals that high electrical input energy facilitates complete decomposition of icosahedral phase into C14 laves and ${\beta}$-(Ti, Zr) phases. Moreover, critical input energy inducing decomposition of the icosahedral phase during EDS depends on the size of the powder. Porous Ti and W compacts have been fabricated by EDS using rectangular and spherical powders upon various input energy at a constant capacitance of $450{\mu}F$ in order to verify influence of powder shape on microstructure of porous compacts. Besides, generated heat (${\Delta}H$) during EDS, which is measured by an oscilloscope, is closely correlated with powder size.

• 한국미생물·생명공학회지
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• 제22권4호
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• pp.389-394
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• 1994

8 X 10$^{6}$(viable cells/ml) of maximum cell density and 9000(IU/ml) of $\gamma$-IFN production were obtained at 55(ml/hr) of a perfusion rate by cultivating HSF cells using a moving membrane aeration bioreactor. This system proves to be an efficient culture process by maintaning 90% of viable cells during the whole cultivation periods. The metabolic molar quotient of glucose to lactate was 0.81 for overall ranges of glucose consumed while the evolution of ammonia was not linearly related to the consumption of glutamine. Low molar conversion ratio was observed in low consumptions of glutamine and high molar conversion ratio in high comsumptions. It also shows that the glutamolysis plays important role in the steady state conditions by evolving larger quantities of ammonia than lactate. At the above of 50 rpm, which is the optimum agitation speed for this bioreactor, the cell growth was severely affected while the IFN production was less decrea- sed, maintaing 1.5 X 10$^{-3}$(IU/cell/day) specific IFN production rate. The cumulatvie $\gamma$-IFN production was 7.2 X 10$^{8}$(IU) for 70 days of the cultivation, which yields 1 X 10$^{7}$ (IU/day) of IFN production rate. Therefore, a commercial production of $\gamma$-IFN by this culture process can be achievable by maintaining the above IFN productivity in a scaled-up culture system.

• 천문학회보
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• 제39권2호
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• pp.50-50
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• 2014

We present a new catalog of galaxies in the wider region of the Virgo cluster, based on the Sloan Digital Sky Survey (SDSS) Data Release 7. The Extended Virgo Cluster Catalog (EVCC) covers an area of 725 deg2 or 60.1 Mpc2. It is 5.2 times larger than the footprint of the classical Virgo Cluster Catalog (VCC) and reaches out to 3.5 times the virial radius of the Virgo cluster. We selected 1324 spectroscopically targeted galaxies with radial velocities less than 3000 km s-1. In addition, 265 galaxies that have been missed in the SDSS spectroscopic survey but have available redshifts in the NASA Extragalactic Database are also included. Our selection process secured a total of 1589 galaxies of which 676 galaxies are not included in the VCC. The certain and possible cluster members are defined by means of redshift comparison with a cluster infall model. We employed two independent and complementary galaxy classification schemes: the traditional morphological classification based on the visual inspection of optical images and a characterization of galaxies from their spectroscopic features. SDSS u, g, r, i, and z passband photometry of all EVCC galaxies was performed using Source Extractor. We compare the EVCC galaxies with the VCC in terms of morphology, spatial distribution, and luminosity function. The EVCC defines a comprehensive galaxy sample covering a wider range in galaxy density that is significantly different from the inner region of the Virgo cluster. It will be the foundation for forthcoming galaxy evolution studies in the extended Virgo cluster region, complementing ongoing and planned Virgo cluster surveys at various wavelengths.

• 천문학회보
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• 제37권1호
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• pp.41.1-41.1
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• 2012

Interactions between the galactic interstellar medium (ISM) and the intra cluster medium (ICM) are believed to be one of the main processes affecting galaxy evolution in cluster environments. The aim of our research is to study the molecular gas properties of a galaxy under the ICM pressure in the cluster environment. It has been well known that cluster galaxies are deficient in atomic hydrogen gas (HI gas) compared to their field counterparts and now there is much evidence that low density ISM is being removed by ram pressure due to ICM wind. Meanwhile, no significant molecular gas deficiency of the cluster galaxy population has been found yet they show overall lower star formation rate than galaxies in the field, and it is still puzzling how the star formation could decrease without stripping of dense molecular gas. To address this issue, we probe the detailed molecular gas properties of NGC 4402, located near the cluster center, as part of a study of four spiral galaxies in the Virgo Cluster. NGC 4402 is well known undergoing ram pressure stripping with a truncated HI disk($D_{HI}/D_{opt}$ - 0.75 and only 36% of HI gas compare to field galaxies of a similar size) and a disturbed gas morphology. Comparing the high resolution 12CO and 13CO data of NGC 4402 from the Sub Millimeter Array (SMA) with existing other wavelength data, we probe the spatial distribution and a physical condition of molecular gas under strong ICM pressure. We discuss the star formation activity might have been altered and hence how the global color of NGC4402 would change in the future.

• Advances in concrete construction
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• 제9권2호
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• pp.217-225
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• 2020

The recovery of waste proves a solution with two impacts: the environmental impact by the reduction of pollution and the gain of the occupied space by this waste, and the economic impact by the use of these lasts in the building and in the area of public works. The present research consists in recovering a waste marble (thrown powder exposed to the different meteorological phenomena) generated by the quarry marble of Fil-fila, located at the east side of Skikda in the north-east of Algeria, and add it, as sand in the composition of sand concrete. To carry out this research, we analyzed the evolution brought by the substitution of ordinary sand by marble waste sand, with 25%, 50%, 75% and 100% on the properties in the fresh state (density, workability and air content) and in the cured state (compressive strength, tensile strength, surface hardness and sound velocity). For durability we tested water absorption by immersion and chloride penetration. The results obtained are compared with control samples of 0% of substitution rate. In order to have a good filling of the voids in the granular skeleton; we added a quantity of limestone recycled fines from the quarries and for a good workability a super-plasticizing additive. The results showed that the partial substitution modified both the fresh and the hardened characteristics of the tested concretes, the durability parameters also improved.

• 자원환경지질
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• 제24권4호
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• pp.409-419
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• 1991

본 연구에서는 북부 미시간지역에 분포하는 세개의 troughes (Marquette, Republic, and Michigan River troughes)가 만나는 지역의 tectonic evolution을 해석하기 위한 stress의 방향 및 변성퇴적암류의 분포를 이해하는데 도움을 주기위하여, 중력탐사를 통하여 연구지역의 기반암구조 및 이를 피복하고 있는 변성퇴적암과의 관계를 해석하였다. 연구지역은 시생대 기반암(Precambrian W)을 원생대의 변성퇴적암이 부정합으로 덮고 있으며, 이들 암석군들은 현저한 밀도의 차이를 보여 본역의 지각구조를 설명하는데 있어서 중력탐사가 효과적이다. $380km^2$에 걸친 연구지역에 340개의 중력기점을 설정하여 측정된 중력은 표준중력 보정과정을 통하여 중력이상도를 작성하였다. Trough내에 퇴적되어 있는 변성퇴적암류를 따라 positive anomaly가 세 trough들의 축을 따라 나타난다. 각 trough들의 지하구조는 Talwani 방법에 의하여 modelling되었으며, 이들의 심도 또한 계산되었다. 그 결과로 Marquette trough는 비대청형으로 남쪽사면에 비하여 북쪽사면이 급경사를 이루고 있다. 세 trough가 합류하는 지점의 기반암구조는 대체로 평평하며, 이것으로 미루어 이 trough들이 거의 동시에 생성되었음을 시사해준다.