• Title/Summary/Keyword: $c_1$-construction

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THREE-STAGED RISK EVALUATION MODEL FOR BIDDING ON INTERNATIONAL CONSTRUCTION PROJECTS

  • Wooyong Jung;Seung Heon Han
    • International conference on construction engineering and project management
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    • 2011.02a
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    • pp.534-541
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    • 2011
  • Risk evaluation approaches for bidding on international construction projects are typically partitioned into three stages: country selection, project classification, and bid-cost evaluation. However, previous studies are frequently under attack in that they have several crucial limitations: 1) a dearth of studies about country selection risk tailored for the overseas construction market at a corporate level; 2) no consideration of uncertainties for input variable per se; 3) less probabilistic approaches in estimating a range of cost variance; and 4) less inclusion of covariance impacts. This study thus suggests a three-staged risk evaluation model to resolve these inherent problems. In the first stage, a country portfolio model that maximizes the expected construction market growth rate and profit rate while decreasing market uncertainty is formulated using multi-objective genetic analysis. Following this, probabilistic approaches for screening bad projects are suggested through applying various data mining methods such as discriminant logistic regression, neural network, C5.0, and support vector machine. For the last stage, the cost overrun prediction model is simulated for determining a reasonable bid cost, while considering non-parametric distribution, effects of systematic risks, and the firm's specific capability accrued in a given country. Through the three consecutive models, this study verifies that international construction risk can be allocated, reduced, and projected to some degree, thereby contributing to sustaining stable profits and revenues in both the short-term and the long-term perspective.

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Spalling of heated high performance concrete due to thermal and hygric gradients

  • Zhang, Binsheng;Cullen, Martin;Kilpatrick, Tony
    • Advances in concrete construction
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    • v.4 no.1
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    • pp.1-14
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    • 2016
  • In this study, high performance concrete beams and prisms with high content of PFA were heated to various temperatures up to $450^{\circ}C$ at heating rates of $1^{\circ}C/min$, $3^{\circ}C/min$ and $10^{\circ}C/min$. The thermal gradient was found to increase first with the heating time until a peak value was reached and then decrease until the thermal equilibrium was reached, measured as $115^{\circ}C$, $240^{\circ}C$ and $268^{\circ}C$ for the three heating rates. Spalling occurred on some specimens when the heating temperature was over $400^{\circ}C$ for heating rates of $3^{\circ}C/min$ and $10^{\circ}C/min$. The hygric gradient was found to reach its maximum when the thermal gradient reached its peak. This study indicates that spalling of HPC could happen when the heating temperature was high enough, and both thermal and hygric gradients reached their maxima.

AN ESCAPE CRITERION FOR THE COMPLEX POLYNOMIAL, WITH APPLICATIONS TO THE DEGREE-n BIFURCATION SET

  • Kim, Young Ik
    • Journal of the Chungcheong Mathematical Society
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    • v.16 no.1
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    • pp.7-14
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    • 2003
  • Let $P_c(z)=z^n+c$ be a complex polynomial with an integer $n{\geq}2$. We derive a criterion that the critical orbit of $P_c$ escapes to infinity and investigate its applications to the degree-n bifurcation set. The intersection of the degree-n bifurcation set with the real line as well as with a typical symmetric axis is explicitly written as a function of n. A well-defined escape-time algorithm is also included for the improved construction of the degree-n bifurcation set.

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Biosynthesis of Lactate-containing Polyhydroxyalkanoates in Recombinant Escherichia coli by Employing New CoA Transferases (재조합 대장균에서 새로운 코엔자임 에이 트랜스퍼레이즈를 이용한 젖산을 모노머로 함유한 폴리하이드록시알칸산 생산 연구)

  • Kim, You Jin;Chae, Cheol Gi;Kang, Kyoung Hee;Oh, Young Hoon;Joo, Jeong Chan;Song, Bong Keun;Lee, Sang Yup;Park, Si Jae
    • KSBB Journal
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    • v.31 no.1
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    • pp.27-32
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    • 2016
  • Several CoA transferases from Clostridium beijerinckii, C. perfringens and Klebsiella pneumoniae were examined for biosynthesis of lactate-containing polyhydroxyalkanoates (PHAs) in recombinant Escherichia coli XL1-Blue strain. The CB3819 gene and the CB4543 gene from C. beijerinckii, the pct gene from C. perfringens and the pct gene from K. pneumoniae, which encodes putative CoA transferase gene, respectively, was co-expressed with the Pseudomonas sp. MBEL 6-19 phaC1437 gene encoding engineered Pseudomonas sp. MBEL 6-19 PHA synthase 1 ($PhaC1_{Ps6-19}$) to examine its activity for the construction of key metabolic pathway to produce poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)]. The recombinant E. coli XL1-Blue expressing the phaC1437 gene and CB3819 gene synthesized poly(3-hydroxybutyrate) [P(3HB)] homopolymer to the P(3HB) content of 60.5 wt% when it was cultured in a chemically defined medium containing 20 g/L of glucose and 2 g/L of sodium 3-hydroxybutyrate. Expression of the phaC1437 gene and CB4543 gene in recombinant E. coli XL1-Blue also produced P(3HB) homopolymer to the P(3HB) content of 51.2 wt% in the same culture condition. Expression of the phaC1437 gene and the K. pneumoniae pct gene in recombinant E. coli XL1-Blue could not result in the production of PHAs in the same culture condition. However, the recombinant E. coli XL1-Blue expressing the phaC1437 gene and the C. perfringens gene could produce poly(3-hydroxybutyrate-co-lactate [P(86.4mol%3HB-co-13.7 mol%LA) up to the PHA content of 10.6 wt% in the same culture condition. Newly examined CoA transfereases in this study may be useful for the construction of engineered E. coli strains to produce PHA containing novel monomer such lactate.

DUALS OF ANN-CATEGORIES

  • Hanh, Dang Dinh;Quang, Nguyen Tien
    • Communications of the Korean Mathematical Society
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    • v.27 no.1
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    • pp.23-36
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    • 2012
  • Dual monoidal category $\mathcal{C}^*$ of a monoidal functor F : $\mathcal{C}\;{\rightarrow}\;\mathcal{V}$ has been constructed by S. Majid. In this paper, we extend the construction of dual structures for an Ann-functor F : $\mathcal{B}\;{\rightarrow}\;\mathcal{A}$. In particular, when F = $id_{\mathcal{A}}$, then the dual category $\mathcal{A}^*$ is indeed the center of $\mathcal{A}$ an this is a braided Ann-category.

A New Chiral Synthetic Route to (+)-Isocarbacyclin

  • HoKoon Park;Yong Sup Lee;Shim Sang Chul
    • Bulletin of the Korean Chemical Society
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    • v.14 no.1
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    • pp.86-91
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    • 1993
  • A synthetic route to (+)-isocarbacyclin starting from (-)-tricyclo[3.3.0.0$^{2.8}$]octan-3-one 6 is described. The key intermediate 4 has been synthesized from 6 by a sequential introduction of methoxycarbonyl group at C-12 and the oxygen functionality at C-9${\alpha}$(PG numbering) for the construction of ${\alpha}-and\;{\omega}$-side chain, and then converted to isocarbacyclin methyl ester 2.

Effect of Alkaline Activator and Curing Condition on the Compressive Strength of Cementless Fly Ash Based Alkali-Activated Mortar (시멘트를 사용(使用)하지 않은 플라이애시 알칼리 활성(活性) 모르타르의 압축강도(壓縮强度)에 미치는 알칼리 활성제(活性劑) 및 양생조건(養生條件)의 영향(影響))

  • Kang, Hyun-Jin;Ryu, Gum-Sung;Koh, Kyung-Taek;Kang, Su-Tae;Park, Jung-Jun;Kim, Sung-Wook;Lee, Jang-Hwa
    • Resources Recycling
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    • v.18 no.2
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    • pp.39-50
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    • 2009
  • Portland cement production is under critical review due to high amount of $CO_2$ gas released to the atmosphere. Attempts to increase the utilization of fly ash, a by-products from thermal power plant to partially replace the cement in concrete are gathering momentum. But most of fly ash is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the source of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effective in the reduction of $CO_2$ gas. In this study, we investigated the influence of the compressive strength of mortar on alkaline activator and curing condition in order to develop cementless fly ash based alkali-activated concrete. In view of the results, we found out that it was possible for us to make alkali-activated mortar with 70MPa at the age of 28days by using alkaline activator manufactured as 1:1 the mass ratio of 9M NaOH and sodium silicate and applying the atmospheric curing after high temperature at $60^{\circ}C$ for 48hours.

Construction of an Integrated Pepper Map Using RFLP, SSR, CAPS, AFLP, WRKY, rRAMP, and BAC End Sequences

  • Lee, Heung-Ryul;Bae, Ik-Hyun;Park, Soung-Woo;Kim, Hyoun-Joung;Min, Woong-Ki;Han, Jung-Heon;Kim, Ki-Taek;Kim, Byung-Dong
    • Molecules and Cells
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    • v.27 no.1
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    • pp.21-37
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    • 2009
  • Map-based cloning to find genes of interest, marker-assisted selection (MAS), and marker-assisted breeding (MAB) all require good genetic maps with high reproducible markers. For map construction as well as chromosome assignment, development of single copy PCR-based markers and map integration process are necessary. In this study, the 132 markers (57 STS from BAC-end sequences, 13 STS from RFLP, and 62 SSR) were newly developed as single copy type PCR-based markers. They were used together with 1830 markers previously developed in our lab to construct an integrated map with the Joinmap 3.0 program. This integrated map contained 169 SSR, 354 RFLP, 23 STS from BAC-end sequences, 6 STS from RFLP, 152 AFLP, 51 WRKY, and 99 rRAMP markers on 12 chromosomes. The integrated map contained four genetic maps of two interspecific (Capsicum annuum 'TF68' and C. chinense 'Habanero') and two intraspecific (C. annuum 'CM334' and C. annuum 'Chilsungcho') populations of peppers. This constructed integrated map consisted of 805 markers (map distance of 1858 cM) in interspecific populations and 745 markers (map distance of 1892 cM) in intraspecific populations. The used pepper STS were first developed from end sequences of BAC clones from Capsicum annuum 'CM334'. This integrated map will provide useful information for construction of future pepper genetic maps and for assignment of linkage groups to pepper chromosomes.

Tunnel lining load with consideration of the rheological properties of rock mass and concrete

  • Lukic, Dragan C.;Zlatanovic, Elefterija M.;Jokanovic, Igor M.
    • Geomechanics and Engineering
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    • v.21 no.1
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    • pp.53-62
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    • 2020
  • Rheological processes in the rock mass for the stress-strain analysis are quite important when considering the construction of underground structures in soft rock masses, particularly in case of construction in several stages. In the analysis, it can be assumed that the reinforced concrete structure is slightly deformable in relation to the rock mass, and the rheological stress redistribution happens at the expense of the elements of rock mass. The basic elements of rheological models for certain types of rock mass and analysis of these models are presented in the first part of this paper. The second part is dedicated to the analysis of rheological processes in marl rock mass and the influence of these processes on the reinforced-concrete tunnel structure.

Gas Transmit Characteristic of Waste Recycling a Large Landfill Cover (폐기물 재활용 대형복토재의 가스투과 특성)

  • Jung, Ha-Ik;Song, Bong-Joon;Kim, Sang-Keun;Kang, Suk-Joo;Lee, Jae-Young
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.1396-1399
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    • 2005
  • Gas permeability of the solidified sewage sludge needs to be characterized in order to use as a large-scale landfill cover material. Four different types of the samples were prepared for gas permeability experiments: (1) granite soil, (2) dried sewage sludge, (3) solidified sewage mixed with slag and (4) solidified sewage mixed with granite soils. The experimental instrumentation and measurement devices were newly designed and created to effectively evaluate gas permeability of the samples.

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