Comparison of the Serviceability Performance of Deflection Criteria for Conventional and High Performance Bridges

Hung X. Le,김도영,황의승 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

The purpose of this paper is to investigate and compare the serviceability performance of deflection criteria for conventional and high performance bridges in terms of applicability and reliability. Experimental studies were performed on fourteen test bridges that represent typical types of conventional and high performance bridges. The measured vibrational characteristics are compared with those from theoretical models to verify the validity of the theoretical models. The verified bridge models are then used to calculate the deflection due to test trucks as well as normal truck traffic collected from a Weigh-In-Motion (WIM) system. To investigate the probabilistic characteristics, the mean maximum deflection for different time periods are determined via extrapolation. Statistical parameters of the probability distribution of deflection are also determined, and then the probabilities of failure and reliability indices are calculated. Finally, the applicability of design code is investigated and compared between conventional and high performance bridges.

Fine mapping of spp7 controlling spikelets per panicle and yield components from Oryza minuta to cultivated rice, O. sativa L.

Le-Hung Linh,Nguyen-Thi Hang,Ju-Won Kang,Sang-Nag Ahn 한국작물학회 2008 한국작물학회 학술발표대회 논문집 Vol.2008 No.10

IL-34 (NIL) developed by introgressing chromosomal segment substitution from an accession of Oryza minuta (2n=48, BBCC, Acc. No. 101141) into the O. sativa subsp. japonica cv. Hwaseongbyeo, showed significantly higher number of spikelets per panicle (SSP) than the recurrent parent Hwaseongbyeo. QTL analysis in F2 generation derived from the cross between IL-34 and Hwaseongbyeo revealed that ssp7, a QTL was located in the pericentromeric region of chromosome 7. The frequency distribution of spikelets per panicle followed 3:1 ratio for single locus segregation. The additive effect of the O. minuta allele at the QTL was 23 spikelets per panicle, and 43.6% of the phenotypic variance could be explained by the segregation of marker RM21596. To clarify whether ssp7 could be dissected genetically, we carried out fine-scale mapping with 3,700 F2 plants derived from the cross between IL-34 and Hwaseongbyeo using markers flanking spp7. 186 F2 plants having informative recombination breakpoints within the region flanked by two SSR markers RM500 and RM21615 were identified and used for fine mapping of ssp7. ssp7 was mapped between the SSR markers RM21596 and RM418 which was approximately 441kb in length based on the physical map of the region. Of great interests, the QTL region also had effects on primary branch number (PB), grains per panicle (SP) and grain yield (YD). These results are very useful for transferring or pyramiding ssp7 by molecular marker assistant selection in rice breeding programs.

PHC 항타말뚝에 대한 CPT 선단 지지력 산정식의 적용성

Le, Chi Hung,정성교,김성렬 한국지반공학회 2009 한국지반공학회논문집 Vol.25 No.12

As CPT penetration tends to show a similar behavior to that of pile driving, a number of methods for estimating the toe bearing capacity of piles based on CPT data have been proposed. To evaluate the applicability of the methods in this country, a total of 172 dynamic load tests data on PHC piles and 82 CPT data at a site in the Nakdong River estuary were collected. A specific four-step procedure was adopted for the selection of the reliable data, and statistical techniques were then applied to the analysis of the applicability. The results indicated that among a total of 10 CPT-based methods applied, the best one is the Aoki method (1975), followed by the LCPC (1982), ICP (2005) methods and others.

Adaptive Reduced Power Subframe in LTE Heterogeneous Networks

Le Hung Nguyen,Minh Thang Nguyen,Sungoh Kwon 한국통신학회 2018 한국통신학회 학술대회논문집 Vol.2018 No.11

An experimental investigation of the cyclic response of bucket foundations in soft clay under one-way cyclic horizontal loads

Hung, Le Chi,Lee, Si-Hoon,Vicent, Ssenyondo,Kim, Sung-Ryul Elsevier 2018 Applied ocean research Vol.71 No.-

<P><B>Abstract</B></P> <P>This study conducted 1 <I>g</I> laboratory tests to investigate the accumulated rotation and unloading stiffness of two model bucket foundations embedded in soft clay under one-way cyclic horizontal loads. The model bucket foundations were specifically designed to have embedment ratios of 0.5 and 1. Ground models were prepared by consolidating the kaolin slurry. One-way cyclic horizontal loads of up to 10<SUP>4</SUP> cycles were applied varying loading magnitudes. Test results showed that the accumulated rotations of the bucket foundations increased with increased number of load cycles and cyclic horizontal load magnitudes. The unloading stiffness of the bucket foundations increased with increasing number of cycles and embedment ratios but decreased with increasing cyclic horizontal load magnitude. Based on the model test results, empirical equations were proposed to evaluate the accumulated rotation and unloading stiffness of the bucket foundations in soft clay under one-way cyclic horizontal loads.</P>

Speaker-Dependent Emotion Recognition For Audio Document Indexing

LE Xuan Hung,Georges QUENOT,Eric CASTELLI 대한전자공학회 2004 International Conference on Electronics, Informati Vol.2004 No.8

An Energy-Efficient Access Control Scheme forWireless Sensor Networks based on Elliptic Curve Cryptography

Le, Xuan Hung,Lee, Sung-Young,Butun, Ismail,Khalid, Murad,Sankar, Ravi,Kim, Miso Hyoung-Il,Han, Man-Hyung,Lee, Young-Koo,Lee, Hee-Jo The Korea Institute of Information and Commucation 2009 Journal of communications and networks Vol.11 No.6

For many mission-critical related wireless sensor network applications such as military and homeland security, user's access restriction is necessary to be enforced by access control mechanisms for different access rights. Public key-based access control schemes are more attractive than symmetric-key based approaches due to high scalability, low memory requirement, easy key-addition/revocation for a new node, and no key predistribution requirement. Although Wang et al. recently introduced a promising access control scheme based on elliptic curve cryptography (ECC), it is still burdensome for sensors and has several security limitations (it does not provide mutual authentication and is strictly vulnerable to denial-of-service (DoS) attacks). This paper presents an energy-efficient access control scheme based on ECC to overcome these problems and more importantly to provide dominant energy-efficiency. Through analysis and simulation based evaluations, we show that the proposed scheme overcomes the security problems and has far better energy-efficiency compared to current scheme proposed byWang et al.

Experimental investigation of the vertical pullout cyclic response of bucket foundations in sand

Hung, Le Chi,Lee, Sihoon,Tran, Nghiem Xuan,Kim, Sung-Ryul Elsevier 2017 Applied ocean research Vol.68 No.-

<P><B>Abstract</B></P> <P>A series of 1g model tests was conducted to investigate the accumulated vertical pullout displacement and unloading stiffness of bucket foundations embedded in dry and saturated sands. The foundations were subjected to vertical pullout cyclic loading with different load amplitudes. Cyclic load was applied up to 10<SUP>4</SUP> cycles. Test results showed that the accumulated vertical pullout displacement increased with the increase in the number of load cycles and cyclic load amplitudes. The unloading stiffness of the bucket foundations decreased with the increase in load amplitude and number of cycles. Empirical equations were proposed based on the test results to evaluate the accumulated vertical pullout displacement and unloading stiffness of the bucket foundations in saturated sand. These equations can be used for the preliminary design of single or tripod bucket foundations.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cyclic response of bucket foundations in saturated sand under cyclic vertical pullout load was examined by 1 <I>g</I> model tests. </LI> <LI> Accumulated displacement increased with the increase in number of load cycles and load magnitude. </LI> <LI> Unloading stiffness decreased with the increase in number of load cycles and load magnitude. </LI> <LI> Empirical equations have been proposed. </LI> </UL> </P>

Investigation of Deflection and Vibration Criteria for Road Bridges

Hung X. Le,황의승 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.3

Deflection and vibration play an important role in the serviceability of bridges. Their limits are specified in design codes either for consideration or as requirements. To promote understanding of the role of deflection and vibration limits, a comprehensive literature review is presented and comparison is made to propose the rational method to control bridge vibration for human comfort. To investigate the vibration and deflection criteria and applicability for bridges, actual bridges to represent typical bridge types are selected for experimental tests and theoretical study. Comparisons of the experimental results of deflection, acceleration, and frequency with the theoretical results are performed to verify the validity of the theoretical models. To ensure the applicability of the design code, bridges are redesigned so that they have minimum capacities as required by the design code. Finally, the vibration parameters of actual bridges and bridges using minimum sections are compared with current design limits and proposed criteria.

Zinc Oxide Wire-Like Thin Films as Nitrogen Monoxide Gas Sensor

Hung, Nguyen Le,Kim, Hyojin,Kim, Dojin Materials Research Society of Korea 2015 한국재료학회지 Vol.25 No.7

We present an excellent detection for nitrogen monoxide (NO) gas using polycrystalline ZnO wire-like films synthesized via a simple method combined with sputtering of Zn metallic films and subsequent thermal oxidation of the sputtered Zn nanowire films in dry air. Structural and morphological characterization revealed that it would be possible to synthesize polycrystalline hexagonal wurtzite ZnO films of a wire-like nanostructure with widths of 100-150 nm and lengths of several microns by controlling the sputtering conditions. It was found from the gas sensing measurements that the ZnO wire-like thin film gas sensor showed a significantly high response, with a maximum value of 29.2 for 2 ppm NO at $200^{\circ}C$, as well as a reversible fast response to NO with a very low detection limit of 50 ppb. In addition, the ZnO wire-like thin film gas sensor also displayed an NO-selective sensing response for NO, $O_2$, $H_2$, $NH_3$, and CO gases. Our results illustrate that polycrystalline ZnO wire-like thin films are potential sensing materials for the fabrication of NO-sensitive high-performance gas sensors.