• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.324-337
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• 2010

For the development of load and resistance factor design, reliability analysis is required to calibrate resistance factors in the framework of reliability theory. The distribution of measured-to-predicted pile resistance ratio was constructed based on only the results of load tests conducted to failure for the assessment of uncertainty regarding pile resistance and used in the conventional reliability analysis. In other words, successful pile load test (piles resisted twice their design loads without failure) results were discarded, and therefore, were not reflected in the reliability analysis. In this paper, a new systematic method based on Bayesian theory is used to update reliability index of driven steel pile piles by adding more pile load test results, even not conducted to failure, into the prior distribution of pile resistance ratio. Fifty seven static pile load tests performed to failure in Korea were compiled for the construction of prior distribution of pile resistance ratio. Reliability analyses were performed using the updated distribution of pile resistance ratio and the total load distribution using First-order Reliability Method (FORM). The challenge of this study is that the distribution updates of pile resistance ratio are possible using the load test results even not conducted to failure, and that Bayesian update are most effective when limited data are available for reliability analysis or resistance factors calibration.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1693-1699
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• 2016

The oscillation character of permanent magnetic motor is highly related to its slot-pole match. By calculating air-gap magnet field and radial electromagnetic force of 6-phase fractional-slot concentrated-winding permanent magnetic motor with slot-pole match of 48/44, 48/46, 48/50 and 48/52 under no load and load status, oscillation character of permanent magnetic motor is analyzed. A 20kW prototype with 48 slots and 44 poles is designed. With many sensors attaching to the corresponding parts, oscillatory acceleration is measured, and spectrum of oscillation frequency is recorded as well. The experiment results give proof to the analysis method for permanent magnetic motor oscillation in this paper.

• Journal of the Korean Institute of Telematics and Electronics
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• v.10 no.4
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• pp.74-79
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• 1973

The Impcdance Matching Condition for maximum power out-pilt cf an Impact oscillator is calculated using the Van der pol's equation. From this calculation, it is found that the load impedance of the oscillator must be one half of the diode impedance for the maximum power output. To get an experimental proof for this result, tole impedance of the Impatt-diode was measured and accordingly the microwave oscillator designed and fabricated. The data obtaiped from the experiments agree fairly closely with the theoretical values.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.2
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• pp.84-93
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• 2000

Computer simulations of the mechanical behavior of 3 point bend specimens with a quarter notch under impact load are performed. This validity is found to be identified by the experimental proof. The cases with various loading rates applied at the side of the specimen are considered. An elastoplastic von Mises material model is chosen. Gap opening displacement, reaction force, crack tip opening displacement and strain rate are also compared with rate dependent material(visco-plastic material). The stability during various dynamic load can be seen by using the simulation of this study. These differences of the cases with various loading rates are also investigated.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.179-185
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• 2002

In this study, the structural design method for the modified long-endurance UAV is presented. Composite materials using room temperature curing method and wet lay up procedure is applied to all wing structures. The modified wing is composed of 3-piece component for improvement of ground handling. As the sandwich structure is efficient for light weight and high stiffness, all skin is used the sandwich consisting of glass/ epoxy fabric and balsa wood. The proof test is performed up to limit load corresponding to 4g load condition for the modified wing structure.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.3
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• pp.273-287
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• 2006

This study investigates the failure mechanism and load-carrying capacity of a single-shell lining which has no disturbance in transfer of shear force, with respect to a conventional double-shell lining which has separation between layers of shotcrete lining and secondary concrete lining by water-proof membrane. In order to evaluate the capacity, a 2-D numerical investigation is preliminarily carried out and then real-scale loading tests with tunnel lining section specimens are performed on the condition given by the numerical investigation. In the test, a concentrated load is applied for considering a released ground load or rock wedge load. Through this study, it appears that the single-shell lining takes the load-bearing capacity 20% higher than in case of the double-shell lining. In addition, a possibility of a composite single-shell shotcrete layer composed by multiple bonded layers partly involving different contents of high-capacity additives is shown thereby leading to use of less amount of the high-capacity additives on the condition of taking a similar load-bearing capacity.

• KIEAE Journal
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• v.6 no.3
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• pp.49-56
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• 2006

The roof among the outer surfaces of buildings is an optimum place to install PV since it is the best favorable part in the building to be exposed to day light. Especially, in case of module of BIPV for Roof, it should have essentially the functions of both electricity generation and roof-finish as a construction material. The followings are the results of the study which has analyzed the architectural conditions and applications thereof at the job site. -The aesthetic function of BIPV module is very important because the roof, mostly located at the top of the buildings, is easily recognized and affects outer interior design of the building a lot. -The heat proof of BIPV for Roof could affect the energy consumption through the roof having a wide area. -For architectural condition to the weather, the roof has to ensure the stability of the weather, humidity proof, and airtightness to the wind respectively. -For architectural condition of the structure, endurance by physical power such as stability of both combining and fixing and transfer of load should be ensured. -For residents protection, it has also architectural functions to secure for the space and shield ozone, UV and noxious substances. -Through its practical applications, It is already confirmed that there are various types of BIPV modules overseas and its application has been proved successfully.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.249-251
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• 2021

PBFT (Practical Byzantine Fault Tolerant) is a consensus algorithm that guarantees higher processing speed compared to PoW (Proof of Work) and absolute finality that records are not overturned due to the superiority of computing power. However, due to the complexity of the message, there is a limit that the network load increases exponentially as the number of participating nodes increases. PBFT is an important factor in determining the performance of a blockchain network, but studies on evaluation metrics and evaluation technologies are lacking. In this paper, we propose a PBFT evaluation framework that is convenient to change the consensus algorithm to easily evaluate quantitative indicators and improved methods for evaluating PBFT.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.226-234
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• 2021

The objective of this study is to establish the fundamental design data for axial load-displacement relationship under axial monotonic or cyclic responses of seismic damping·isolation (SDI) units developed for ceiling structures. The main parameters include the installation of a spring, the number of rubber layer, prestress stress of bolts for connector between the spring and rubbers, and loading type. Test results showed that SDI units with a spring in the core and higher prestress stress of bolts tended to be higher stiffness at the ascending branch and more ductile behavior at the descending branch. This trends more notable for the specimens under monotonic load rather than cyclic loads. Consequently, the energy dissipation of SDI unit can be optimally designed with the following conditions: installation of a spring within 3-layer rubbers and prestress applied to the bolts at 10% of their yielding strength . When compared with the experimental tension capacity of the developed SDI units, the predictions by JIS B 2704-1 and KDS 31 00 are conservative under monotonic loading but higher by approximately 10% under cyclic loading.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.816-823
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• 2007

As the South Korean rolling stock industry is developing designs for full compliance with the European Standards, it is fitting to take a look at these two core standards. The paper presents an overview of the load cases and structural requirements developed in Europe for the design of safe and compatible rolling stock vehicles. These load cases and structural requirements have been compiled into two standards namely EN12663 and EN15227. Standard EN12663 was developed as a reference design requirements standard. The work was mandated and sponsored by the European Committee for Standardization and Standard issuing National Institutions. EN12663 specifies a series of proof and fatigue load cases for European rolling stock regulations compliant vehicle designs. As EN12663 does not address the crashworthiness issue, a dedicated crashworthiness standard, EN15227, was therefore developed in a similar manner through industry wide consultations managed by a Trans-European working group of experienced engineers and specialists. In both standards, the vehicle and/or trains are grouped into categories reflecting the vehicle types and/or their indented operational function. EN15227, developed to complement EN12663, addresses the "passive" crashworthiness capability of the vehicles and trains. EN15227 specifies reference crash scenarios similar to those found in the Technical Specification for Interoperability (TSI) of high speed trains operating in Europe. The overview also touches on a general comparison with the corresponding British Group Standard (GM/RT2100) and also the UIC leaflet based load cases. The exercise is extended to pertinent design load cases specified by the Federal Railroad Administration (FRA) in the US.