Kwang Jo Jeong

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Papers by Kwang Jo Jeong

Effects of Fiscal Consolidation in 18 OECD Countries

Seoul Journal of Economics, Apr 1, 2017

I am grateful to Professor Soyoung Kim, Anonymous referees and Editorial Manager of SJE Jin-hee C... more

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Building Complementarity and Resilience in ASEAN amid Global Trade Uncertainty

ADB briefs, Oct 1, 2018

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A general coincidence theorem on contractible spaces

Proceedings of the American Mathematical Society, 1996

We obtain a general coincidence theorem for multifunctions in very large classes defined on contr... more

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Building Complementarity and Resilience in ASEAN amid Global Trade Uncertainty

ADB Briefs, 2018

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Fixed Point and Non-Retract Theorems – Classical Circular Tours

Taiwanese Journal of Mathematics, 2001

We show that the Brouwer fixed point theorem is equivalent to a number of results closely related... more We show that the Brouwer fixed point theorem is equivalent to a number of results closely related to the Euclidean spaces or n-simplexes or n-balls. Among them are the Sperner lemma, the KKM theorem, some intersection theorems, various fixed point theorems, an intermediate value theorem, various non-retract theorems, the non-contractibility of spheres, and others.

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Manufacturing and Utilization of Pelletized Livestock Manure Compost

Global Journal of Animal Scientific Research, Sep 20, 2014

As of March 2011, there were about 3.3 million cattle, 7 million pigs, and 140 million poultry in... more As of March 2011, there were about 3.3 million cattle, 7 million pigs, and 140 million poultry in Republic of Korea, producing about 46.5 million tons of animal manure. About 87% of the total produced waste is recycled to land as compost and liquid organic fertilizer. Compost made from livestock manure is an effective material for improving the physical and chemical condition of soil. However, there are few factors that limit the application of ordinary composted livestock manure. The major problem is that composted livestock manure usually has high moisture content, which deters to produce pelletized compost. This study was carried out to develop a new type of pelletizing system for high quality pelletized compost. Pilot scale pelletizing instrument system was developed, which can directly manufacture wet compost into pelletized compost without pre-drying of raw material. By using this pelletizing process, weight and volume of compost, and odor were reduced by 30%, respectively. Furthermore, nutrients of compost were not affected by pelletizing process. The High Heating Value (HHV) of pelletized compost with bedding material was 4,135 kcal/kg. As a result, pelletized compost could be used as good quality organic compost and a fuel for burner.

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Local Failure Modes of a Nuclear Reactor Pressure Vessel Nozzle Under Severe Accident Conditions

New and Emerging Computational Methods: Applications to Fracture, Damage, and Reliability, 2002

Most past studies for the creep rupture of a nuclear reactor pressure vessel (RPV) lower head und... more Most past studies for the creep rupture of a nuclear reactor pressure vessel (RPV) lower head under severe accident conditions, have focused on global deformation and rupture modes. Limited efforts were made on local failure modes associated with penetration nozzles as a part of TMI-2 Vessel Investigation Project (TMI-2 VIP) in 1990’s. However, it was based on an excessively simplified shear deformation model. In the present study, the mode of nozzle failures is investigated using data and nozzle materials from Sandia National Laboratory’s Lower Head Failure Experiment (SNL-LHF). Crack-like separations were revealed at the nozzle weld metal to RPV interfaces indicating the importance of normal stress component rather than the shear stress in the creep rupture. Creep rupture tests were conducted for nozzle and weld metal materials, respectively, at various temperature and stress levels. Stress distribution in the nozzle region is calculated using elastic-viscoplastic finite element analysis (FEA) using the measured properties. Calculation results are compared with earlier results based on the pure shear model of TMI-2 VIE It has been concluded from both LHF-4 nozzle examination and FEA that normal stress at the nozzle/lower head interface is the dominant driving force for the local failure with its likelihood significantly greater than previously assumed.Copyright © 2002 by ASME

ID-Based Secure Session Key Exchange Scheme to Reduce Registration Delay with AAA in Mobile IP Networks

Lecture Notes in Computer Science, 2005

Due to an increasing number of portable devices, a support for quality of service (QoS) and secur... more Due to an increasing number of portable devices, a support for quality of service (QoS) and security becomes an main issue in Mobile IP networks. However Authentication, Authorization, and Accounting (AAA) protocol has inefficient authenticating procedures that limit its QoS. That is, a mobile node (MN) should be distributed new session keys whenever it performs a handoff. As computing power of mobile devices becomes greater, a key distribution using a symmetric key cannot guarantee the security. Hence, we employ an ID-based cryptography to intensify the security and when the MN moves to a new domain, a foreign agent (FA) reuses previous session keys encrypted by a public key for the fast handoff. Our proposed scheme reduces handoff delay and maintains high security by exchanging previous session keys between FAs. The performance results show that the proposed scheme reduces the latency up to about 63% compared to the previous ID-based AAA.

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The Usefulness of Calcium Sulfate in Treatment of Benign Bone Tumor

The Journal of the Korean Orthopaedic Association, 2007

Purpose: This study evaluated the results of the curettage and grafting of calcium sulfate for th... more Purpose: This study evaluated the results of the curettage and grafting of calcium sulfate for the treatment of a benign bone tumor to determine its efficacy as a bone graft substitute. Materials and Methods: Thirty six cases of calcium sulfate(Osteoset Ⓡ) grafting for bone defect after curettage of benign bone tumor were evaluated. There were 21 males and 15 females with a mean age of 23 years (6-64). There were 23, 10 and 3 cases grafted with the Osteoset only, the Osteoset with allografts and the Osteoset with autografts, respectively. The average follow up duration was 19 months (12-49). The process of bone formation was observed and the times for graft absorption and complete bone formation were assessed. In addition, the time of bone formation was compared according to the patients' age, size of lesion, and grafting method, and the development of complications was observed. Results: Complete bone formation was observed in 34 (94.4%) out of 36 cases. The groups of younger patients, smaller size of lesion and grafting of Osteoset Ⓡ only showed more rapid bone formation. However, there was no statistical significance. There was one case of soft tissue calcification observed. Conclusion: Calcium sulfate is an effective substitute for an autogenous bone graft in the case of the treatment of a benign bone tumor, particularly in the case of an insufficient graft, such as in children and in those with a large bone defect. This method is a safe method that prevents complications in the donor site.

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Epidemiology and genetics of hypodontia and microdontia: A study of twin families

The Angle orthodontist, Jan 22, 2014

Objective: To identify genetic and environmental factors contributing to hypodontia and microdont... more Objective: To identify genetic and environmental factors contributing to hypodontia and microdontia by using Korean twin family data. Materials and Methods: A total of 1267 individuals (525 men and 742 women; 180 monozygotic twins [MZ] and 43 dizygotic twins [DZ] from 282 families) underwent an oral examination as part of the Healthy Twin Study in Korea. Dental anomalies classified as hypodontia or microdontia were diagnosed using radiographs and clinical examinations. In order to estimate genetic contributions to dental anomalies, we estimated the pairwise concordance rate (PCR), recurrence risk ratio (RRR), and heritability (h2). Results: The prevalence of hypodontia and microdontia was 3.55% and 3.00%, respectively. MZ had the highest PCR and RRR (13.0-15.3). The PCR and RRR values for both anomalies were much higher for DZ (5.0-11.9) than for siblings (1.4-2.6), despite the fact that DZ pairs and sibling pairs share 50% genetic identity. Further genetic analysis revealed both an...

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Higgs phenomenology in the Peccei-Quinn invariant NMSSM

Journal of High Energy Physics, 2014

Bottom nozzle failure mechanism of water reactor pressure vessel under severe accident conditions

Nuclear Engineering and Design, 2007

Most of past studies devoted to the creep rupture of a nuclear reactor pressure vessel (RPV) lowe... more Most of past studies devoted to the creep rupture of a nuclear reactor pressure vessel (RPV) lower head under severe accident conditions, have focused on global deformation and rupture modes. Limited efforts were made on local failure modes associated with penetration nozzles as a part of TMI-2 vessel investigation project (TMI-2 VIP) in 1990s. However, it was based on an excessively simplified shear deformation model. In the present study, the mode of nozzle failure has been investigated using data and nozzle materials from Sandia National Laboratory's lower head failure experiment (SNL-LHF). Crack-like separations were revealed at the nozzle weld metal to RPV interfaces indicating the importance of normal stress component rather than the shear stress in the creep rupture. Creep rupture tests were conducted for nozzle and weld metal materials, respectively, at various temperature and stress levels. Stress distribution in the nozzle region is calculated using elastic–viscoplastic finite element analysis (FEA) using the measured properties. Calculation results are compared with earlier results based on the pure shear model of TMI-2 VIP. It is concluded from both LHF-4 nozzle examination and FEA that normal stress at the nozzle/lower head interface is the dominant driving force for the local failure. From the FEA for the nozzle weld attached in RPV, it is shown that nozzle welds failure occur by displacement controlled fracture of nozzle hole not by load controlled fracture of internal pressure. Considering these characteristics of nozzle weld failure, new concept of nozzle failure time prediction is proposed.

Design and manufacture of a three-axis ultra-precision CNC grinding machine

Journal of Materials Processing Technology, 1997

A three-axis CNC grinding machine tool for the ultra-precision mirror surface grinding of advance... more A three-axis CNC grinding machine tool for the ultra-precision mirror surface grinding of advanced materials such as ceramics and other hard and brittle materials has been designed. The grinding machine is composed of the air spindle, a high-damping resin concrete bed, and a three-axis CNC controller with high resolution AC servo motors.For the stiffness calculations of the grinding machine, a

Thermal inflation and baryogenesis in heavy gravitino scenario

Journal of Cosmology and Astroparticle Physics, 2009

Production of methanethiol and volatile sulfur compounds by the archaeon “Ferroplasma acidarmanus”

Extremophiles, 2007

Acidophiles are typically isolated from sulfaterich ecological niches yet the role of sulfur meta... more Acidophiles are typically isolated from sulfaterich ecological niches yet the role of sulfur metabolism in their growth and survival is poorly defined. Studies of heterotrophically grown ''Ferroplasma acidarmanus'' showed that its growth requires a minimum of 100 mM of a sulfate-containing salt. Headspace gas analyses by GC/ MS determined that the volatile sulfur compound emitted by active ''F. acidarmanus'' cultures is methanethiol. In ''F. acidarmanus'' cultures grown either heterotrophically or chemolithotrophically, methanethiol was produced constitutively. Radiotracer studies with 35S-labeled methionine, cysteine, and sulfate showed that all three were used in methanethiol production. Additionally, 3H-labeled methionine was incorporated into methanethiol and was probably used as a methyl-group donor. Methanethiol production in whole cell lysates supplied with SO3 2-indicated that NADPH-dependant sulfite reductase and methyltransferase activities were present. Cell lysates also contained enzymatic activity for methionine-c-lyase that cleaved the side chain of either methionine to form methanethiol or cysteine to produce H2S. Since methanethiol was detected from the degradation of cysteine, it is likely that sulfide was methylated by a thiol methyltransferase. Collectively, these data demonstrate that ''F. acidarmanus'' produces methanethiol through the metabolism of methionine, cysteine, or sulfate. This is the first report of a methanethiol-producing acidophile, thus identifying a new contributor to the global sulfur cycle.

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Heuristics for selecting machines and determining buffer capacities in assembly systems

Computers & Industrial Engineering, 2000

This paper considers a design problem of assembly systems consisting of stations and buffers that... more This paper considers a design problem of assembly systems consisting of stations and buffers that connect the stations. We present a solution procedure for ®nding the minimum cost con®guration which gives a desired throughput rate for an assembly system. The con®guration is de®ned by the machines to be used in stations (machine con®guration) and capacities of buffers. Three heuristics are proposed, which simultaneously select the machines to be used in the stations and determine the capacities of the buffers. These heuristics start from an initial con®guration such as a lower con®guration, which consists of less ef®cient machines and large size buffers, or an upper con®guration, which consists of more ef®cient machines and small size buffers. Then, the heuristics search for a near optimal solution by repeatedly generating promising machine con®gurations and determining (near) optimal buffer sizes for the machine con®gurations. Results of computational experiments show that the proposed heuristics give relatively good con®gurations in a reasonable amount of time.

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Design and manufacture of the composite flexspline of a harmonic drive with adhesive joining

Composite Structures, 1994

ABSTRACT

Development of the anthropomorphic robot with carbon fiber epoxy composite materials

Composite Structures, 1993

... In order to determine the torque capacity of the adhesively bonded joint, the torque capacity... more

Growth of Carbon Nanotubes on Anodic Aluminum Oxide Templates: Fabrication of a Tube-in-Tube and Linearly Joined Tube

Chemistry of Materials, 2001

We have fabricated multiwalled carbon nanotubes (CNTs) with flowing acetylene, using a well-order... more We have fabricated multiwalled carbon nanotubes (CNTs) with flowing acetylene, using a well-ordered porous anodic aluminum oxide (AAO) nanotemplate with or without deposition of Co in the pores as a catalyst. Without deposition of Co, the tubes were made in the pores having the shape of the pores by catalysis with the alumina of the AAO templates. With deposition of Co, both alumina and Co could work as a catalyst. By widening the pores after Co deposition, tubes grow out from the pores, by forming a tube-in-tube, which could be used for electrochemical energy storage. Since the alumina of the AAO templates works as a catalyst, one can fabricate special shapes of CNTs by designing the pores of AAO templates. We have succeeded for the first time to fabricate linearly joined CNTs by using AAO templates prepared by using pore widening and multianodization techniques. The electronic properties of the linearly joined CNTs will be affected critically by the junctions that contain five-and seven-membered carbon ring defects and could be controlled by changing the ratio of the two diameters of them. A schematic to fabricate FET (field-effect transistor) using the linearly joined CNTs fabricated on AAO templates has been suggested.

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Acid stress damage of DNA is prevented by Dps binding in Escherichia coliO157:H7

BMC Microbiology, 2008

Background Acid tolerance in Escherichia coli O157:H7 contributes to persistence in its bovine ho... more Background Acid tolerance in Escherichia coli O157:H7 contributes to persistence in its bovine host and is thought to promote passage through the gastric barrier of humans. Dps (DNA-binding protein in starved cells) mutants of E. coli have reduced acid tolerance when compared to the parent strain although the role of Dps in acid tolerance is unclear. This study investigated the mechanism by which Dps contributes to acid tolerance in E. coli O157:H7. Results The results from this study showed that acid stress lead to damage of chromosomal DNA, which was accentuated in dps and recA mutants. The use of Bal31, which cleaves DNA at nicks and single-stranded regions, to analyze chromosomal DNA extracted from cells challenged at pH 2.0 provided in vivo evidence of acid damage to DNA. The DNA damage in a recA mutant further corroborated the hypothesis that acid stress leads to DNA strand breaks. Under in vitro assay conditions, Dps was shown to bind plasmid DNA directly and protect it from ...

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Effects of Fiscal Consolidation in 18 OECD Countries

Seoul Journal of Economics, Apr 1, 2017

I am grateful to Professor Soyoung Kim, Anonymous referees and Editorial Manager of SJE Jin-hee C... more

Download

Building Complementarity and Resilience in ASEAN amid Global Trade Uncertainty

ADB briefs, Oct 1, 2018

Download

A general coincidence theorem on contractible spaces

Proceedings of the American Mathematical Society, 1996

We obtain a general coincidence theorem for multifunctions in very large classes defined on contr... more

Download