• Proceedings of the Korean Magnestics Society Conference
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• 2002.04a
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• pp.42-43
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• 2002

• Proceedings of the Korean Magnestics Society Conference
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• 2001.10a
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• pp.72-73
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• 2001

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.109-116
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• 2012

This study is aiming to separate highway entrance ramps from impact zones which are considered the characteristics and real traffic situations in each lane and section. The results of this study can be applied to Lane Control System and control the traffic flow for highway more efficiently. Based on earlier studies which analyzed impact zones in entrance-ramp junction using the standard deviation of speed, this study divides more segmentalized impact zones according to the degree of turbulences. As a result of this study, about 800m of intervals, from 500m of upper flow (1,2,3 lane) to 300m of lower flow(2, 3 lane), shows similar traffic characteristics influenced by entrance ramp directly.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.75-77
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• 2003

We have measured the escape rates of the Nb Josephson junction from its zero-voltage state. The critical current measurements were carried out in repeatedly sweeping the current-voltage characteristics of the junction with a current ramp. From the distribution of the critical current the escape temperature was determined by applying the thermal activation model.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.179-183
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• 2000

For a ground plane in high-temperature superconducting ramp-edge junction devices, YBa$_2$Cu$_3$O$_{7-{\delta}}$/SrTiO$_3$/YBa$_2$Cu$_3$O$_{7-{\delta}}$ multilayer structures were fabricated using pulsed laser deposition and ECR ion milling. Various process parameters were adjusted to enhance the device characteristics. By etching the STO layer to form a tapered edge of about 15$^{\circ}$ and in-situ RF plasma treatment of bottom YBCO surface prior to deposition of top YBCO, the top-to-bottom YBCO showed T$_c$ of 75${\sim}$80 K and I$_c$ of about 40 mA through holes. It was found that the deposition of bottom YBCO at a reduced laser repetition rate of 1Hz increased the T$_c$ of top YBCO to 79.9 K. The resistivity of 570 layer was about 10$^6$ ${\Omega}$cm at 60 K, which ensures good electrical isolation between successive YBCO layers.

• Journal of Korean Port Research
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• v.14 no.2
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• pp.175-185
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• 2000

Today freeway is experiencing a severe congestion with incoming or outgoing traffic through freeway ramps during the peak periods. Thus, the purpose of this study is to identify the traffic characteristics, analyze the relationships between the traffic characteristics and finally construct the delay predictive models on the rap junctions of freeway with 70mph speed limit. From the traffic analyses, and model construction and verification for delay prediction on the ramp junctions of freeway, the following results were obtained : ⅰ) Traffic flow showed a big difference depending on the time periods. Especially, more traffic flows were concentrated on the freeway junctions in the morning peak period. ⅱ) The occupancy also showed a big difference depending on the time periods, and the downstream occupancy(Od) was especially shown to have a higher explanatory power for the delay predictive model construction on the ramp junctions of freeway. ⅲ) The delay-occupancy curve showed a remarkable shift based on the occupancies observed : O$\_$d/〈9% and O$\_$d/$\geq$9%. Especially, volume and occupancy were shown to be highly explanatory for delay prediction on the ramp junctions of freeway under O$\_$d/$\geq$9%, but lowly for delay prediction on the ramp junctions of freeway under O$\_$d/〈9%. Rather, the driver characteristics or transportation conditions around the freeway were thought to be a little higher explanatory for the delay prediction under O$\_$d/〈9%. ⅳ) Integrated delay predictive models showed a higher explanatory power in the morning peak period, but a lower explanatory power in the non-peak periods.

• Progress in Superconductivity
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• v.3 no.1
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• pp.83-86
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• 2001

We have fabricated a single flux quantum 4-stage shift register with interface-controlled $Y_1$$Ba_2$$Cu_3$$O_{7-x}$(YBCO) Josephson junction. The YBCO Josephson junctions showed RSJ-like current-voltage(I-V) curves at temperatures 45~80K. We tested load and shift operation of shift register with binary data sequences “1000”, “1010”, “1011”, and “1111” at 58K. For all the binary data sequences, the shift register operated successfully. By operating the circuit with proper current pulses, we observed no errors during at least 12 hours operation for all the data sequences.s.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.63-66
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• 1999

We fabricated ramp-edge Josephson junctions with barriers formed by interface treatments instead of epitaxially grown barrier layers. Low-dielectric Sr$_2AITaO_6$(SAT) layer was used as an ion-milling mask as well as an insulating layer for the ramp-edge junctions. An ion-milled YBa$_2Cu_3O_{7-x}$ (YBCO)-edge surface was not exposed to solvent through all fabrication procedures. The barriers were produced by structural modification at the bottom YBCO edge using plasma treatment prior to deposition of the top YBCO electrode. We investigated the effects of pre-annealing and post-annealing on the characteristics of the interface-treated Josephson junctions. The junction parameters were improved by using in-situ RF plasma cleaning treatment.

• Journal of Korean Society of Steel Construction
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• v.9 no.1 s.30
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• pp.51-63
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• 1997

Highly curved steel-box bridges are usually constructed as ramp structures for the highway interchange and metropolitan elevated highway junction, but a number of these bridges are deteriorated and damaged to a significant degree due to heavy traffic. The main objective of the study is to develop a practical reliability-based assessment of safety and residual load carrying-capacity of existing curved steel-box ramp bridges. In the paper, for the realistic assessment of safety and residual load carrying-capacity of deteriorated and/or damaged curved steel-box bridges, an interactive non-linear limit state model is formulated based on the von Mises's combined stress yield criterion. It is demonstrated that the proposed model is effective for the assessment of reliability-based safety and the evaluation of residual load carrying-capacity of curved steel-box bridges. In addition, this study comparatively shows the applicability of various reliability analysis methods, and suggests a practical and effective one to be used in practice.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.59-66
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• 2006

This study was to construct the linear density predictive models on the on-ramp junctions in urban freeway. From the analyses of the real-time traffic characteristic data, and the construction and verification of the linear density predictive models, the models showed a considerable explanatory power with the determination coefficients ($R^2$) of over 0.7 between the density and speed data. Also, they showed a considerably high correlativeness with the correlation coefficients (r) of over 0.8 between the calculated density data and the expected ones estimated by the models.