• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.5
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• pp.675-682
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• 2013

Reliability analysis and prediction of next failure time is critical to sustain weapon systems, concerning scheduled maintenance, spare parts replacement and maintenance interventions, etc. Since 1981, many methodology derived from various probabilistic and statistical theories has been suggested to do that activity. Nowadays, many A.I. tools have been used to support these predictions. Support Vector Regression(SVR) is a nonlinear regression technique extended from support vector machine. SVR can fit data flexibly and it has a wide variety of applications. This paper utilizes SVM and SVR with combining time series to predict the next failure time based on historical failure data. A numerical case using failure data from the military equipment is presented to demonstrate the performance of the proposed approach. Finally, the proposed approach is proved meaningful to predict next failure point and to estimate instantaneous failure rate and MTBF.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.61
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• pp.75-87
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• 2000

This paper proposes a procedure for designing an accelerated test using SMAT(Stress, (failure) Mechanism and Test) model describing the relation among stress, failure mode/mechanism and test method. In SMAT model the stresses to be applied are derived from the environmental factor analysis, the relative importance of those stresses can be estimated using AHP(Analytic Hierarchy Process) and failure mode/mechanism and test method are derived from the fields failure information and FMEA(Failure Mode and Effect Analysis). By applying the procedure we can make a selection of major factors to cause the failure of assembly and design the accelerated test using DOE(Design of Experiments) The procedure is illustrated with an qualification test case study of washing machine shaft assembly in "A" electric appliance company.

• Structural Engineering and Mechanics
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• v.32 no.2
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• pp.301-320
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• 2009

Damage assessment for buried structures against an internal blast is conducted by considering the soil-structure interaction. The structural element under analysis is assumed to be rigid-plastic and simply-supported at both ends. Shear failure, bending failure and combined failure modes are included based on five possible transverse velocity profiles. The maximum deflections with respect to shear and bending failure are derived respectively by employing proper failure criteria of the structural element. Pressure-Impulse diagrams to assess damage of the buried structures are subsequently developed. Comparisons have been done to evaluate the influences of the soil-structure interaction and the shear-to-bending strength ratio of the structural element. A case study for a buried reinforced concrete structure has been conducted to show the applicability of the proposed damage assessment method.

• Journal of Drive and Control
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• v.15 no.4
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• pp.23-29
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• 2018

The objective of this paper is to evaluate the reliability of a volute pump and presents test results through performance and life tests. The performance and life test methods were presented by analyzing the failure modes of the volute pump. Zero failure test time was calculated to evaluate the reliability of the volute pump and then, the test was performed under accelerated conditions. The test was also carried out to check the failure modes of the field conditions. This study can be provided to improve the product reliability through failure analysis of the volute pump. And failure cause of typical failure case has been investigated and improvement design has been presented. The performance test results of before and after the accelerated life test were presented to confirm the improved reliability of the volute pump.

• Wind and Structures
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• v.34 no.2
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• pp.161-171
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• 2022

This paper presents a failure type assessment curve method to judge the failure type of transmission tower segments. This novel method considers the equivalent static wind load characteristics and the transmission tower members' load-bearing capacities based on numerical simulations. This method can help judge the failure types according to the relative positions between the actual state points and the assessment curves of transmission tower segments. If the extended line of the actual state point intersects with the horizontal part's assessment curve, the segment would lose load-bearing capacity due to the diagonal members' failure. Another scenario occurs when the intersection point is in the oblique part, indicating that the broken main members have caused the tower segment to fail. The proposed method is verified by practical engineering case studies and static tests on the scaled tower segments.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.12
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• pp.253-276
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• 1999

CISG articles 34 and 37 clearly allow the seller to cure any nonconformity in documents of sale or performance prior to the date for delivery if it does not cause the buyer unreasonable inconvenience or unreasonable expense. CISG article 48 allows a seller to cure the performance even after the date for delivery if it does not cause the buyer unreasonable delay, unreasonable inconvenience or unreasonable uncertainty of reimbursement by the seller of expenses advanced by the buyer. The wording any failure to perform is broad enough to include a delay. The seller's right to cure relates to all his obligations. The seller may remedy 'any failure to perform his obligations'. This language is broad enough to include a defect in documents. In some cases the fact that the seller is able and willing to remedy the non-conformity of the goods without inconvenience to the buyer, may mean that there would be no fundamental breach unless the seller failed to remedy the non-conformity within an appropriate time. It cannot generally be said what unreasonable inconvenience means. This can only be decided on a case-by-case basis. The seller must bear the costs involved in remedying a failure to perform. The curing of a failure to perform may have influence on the amount of the damage claimed. Insofar as the seller has the right to cure, the buyer is in that case obliged to accept the cure. If he refuses to do so, he can neither avoid the contract nor declare a reduction in price. This rule clearly shows the underlying concept of the CISG, to keep to the contract, if possible. Should the buyer requires delivery of substitute goods and the seller offers repair, it depends on the expense each case. The buyer must receive the request or notice by the seller. The relationship between the seller's right to cure and the buyer's right to avoid the contract is unclear. The buyer's right to avoid the contract should not nullify the seller's right to cure if the offer is reasonable. In addition, whether a breach is fundamental should be decided in the right of the seller's offer to cure.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.32-40
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• 2011

The PPPs(public private partnerships) which was introduced in the later part of the 1990s has grown since 2005, with the beginning of BTL(Build Transfer Lease) type which retrieves the investment by receiving the lease payment from the government. As application areas and scale of the PPPs have been further expanded, it is expected the demand on special purpose facilities will be increased. We do know only successful foreign practices of the PPPs but have rarely consider the failure cases. Therefore, this paper derives implications by analyzing the case of National physical laboratory project which is known as a typical failure case of UK's PFI. We find that from the perspective of governance, the reasons leading to the failure of business are an insufficient of technical rationality, unsettled social relationships and inefficient risk management. Based on the case study, this study shows how to improve management system for special purpose PPPs business in Korea.

• Geomechanics and Engineering
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• v.22 no.4
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• pp.319-328
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• 2020

This paper investigates the effect of the width of failure and tension crack (TC) on the stability of cohesive-frictional soil slopes in three dimensions. Working analytically, the slip surface and the tension crack are considered to have spheroid and cylindrical shape respectively, although the case of tension crack having planar, vertical surface is also discussed; the latter was found to return higher safety factor values. Because at the initiation of a purely rotational slide along a spheroid surface no shear forces develop inside the failure mass, the rigid body concept is conveniently used; in this respect, the validity of the rigid body concept is discussed, whilst it is supported by comparison examples. Stability tables are given for fully drained and fully saturated slopes without TC, with non-filled TC as well as with fully-filled TC. Among the main findings is that, the width of failure corresponding to the minimum safety factor value is not always infinite, but it is affected by the triggering factor for failure (e.g., water acting as pore pressures and/or as hydrostatic force in the TC). More specifically, it was found that, when a slope is near its limit equilibrium and under the influence of a triggering factor, the minimum safety factor value corresponds to a near spherical failure mechanism, even if the triggering factor (e.g., pore-water pressures) acts uniformly along the third dimension. Moreover, it was found that, the effect of tension crack is much greater when the stability of slopes is studied in three dimensions; indeed, safety factor values comparable to the 2D case are obtained.

• Asia Marketing Journal
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• v.9 no.3
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• pp.75-115
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• 2007

This study investigated the effect of service provider's recovery effort and pre-failure customer-employee rapport on post-recovery consumer response such as satisfaction, purchase intention, and positive Word-of-Mouth communication. First, this study explored the interaction effect of recovery effort and customer-employee rapport on post-recovery consumer response. The result shows when the level of pre-failure customer-employee rapport is high, customer's positive responses decreased slightly even though they perceived low recovery effort. However, when the level of pre-failure customer-employee rapport is low, customer's responses were decreased considerably in case of low recovery effort. Second, this study examined 'service recovery paradox' which is post-recovery consumer's satisfaction is greater than the case of no service failure. The result shows recovery paradox was not supported in all samples regardless of the level of recovery effort and customer-employee rapport. Synthetically, customer-employee rapport took a buffering role in customer response after service failure although it's not the same as error-free state.

• Geomechanics and Engineering
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• v.35 no.5
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• pp.511-523
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• 2023

Canal-side roads frequently collapse due to an unexpectedly greater soft-clay thickness with a rapid drawdown situation. This causes annually increased repair and reconstruction costs. This paper aims to explore the effect of soft-clay thickness on the failure in the canal-side road in the case study of Phra Nakhon Si Ayutthaya rural road no. 1043 (AY. 1043). Before the actual construction, a field vane shear test was performed to determine the undrained shear strength and identify the thickness of the soft clay at the AY. 1043 area. After establishing the usability of AY. 1043, the resistivity survey method was used to evaluate the thickness of the soft clay layer at the failure zone. The screw driving sounding test was used to evaluate the undrained shear strength for the road structure with a medium-stiff clay layer at the failure zone for applying to the numerical model. This model was simulated to confirm the effect of soft-clay thickness on the failure of the canal-side road. The monitoring and testing results showed the tendency of rapid drawdown failure when the canal-side road was located on > 9 m thick of soft clay with a sensitivity > 4.5. The result indicates that the combination of resistivity survey and field vane shear test can be successfully used to inspect the soft-clay thickness and sensitivity before construction. The preliminary design for preventing failure or improving the stability of the canal-side road should be considered before construction under the critical thickness and sensitivity values of the soft clay.