• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.9 no.3
• /
• pp.306-311
• /
• 2016

Software reliability in the software development process is an important issue. Infinite failure NHPP software reliability models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, reliability software cost model considering logarithmic and exponential fault detection rate based on observations from the process of software product testing was studied. Adding new fault probability using the Goel-Okumoto model that is widely used in the field of reliability problems presented. When correcting or modifying the software, finite failure non-homogeneous Poisson process model. For analysis of software reliability model considering the time-dependent fault detection rate, the parameters estimation using maximum likelihood estimation of inter-failure time data was made. The logarithmic and exponential fault detection model is also efficient in terms of reliability because it (the coefficient of determination is 80% or more) in the field of the conventional model can be used as an alternative could be confirmed. From this paper, the software developers have to consider life distribution by prior knowledge of the software to identify failure modes which can be able to help.

• Journal of Korea Water Resources Association
• /
• v.40 no.12
• /
• pp.943-956
• /
• 2007

Among various statistics, the spatial correlation function, that is "correlogram", is frequently used to evaluate or design the rain gauge network and to model the rainfall field. The spatial correlation structure of rainfall has the significant variation due to many factors. Thus, the variation of spatial correlation structure of rainfall causes serious problems when deciding the spatial correlation function of rainfall within the basin. In this study, the spatial rainfall structure was modeled using bivariate mixed distributions to derive monthly spatial correlograms, based on Gaussian and lognormal distributions. This study derived the correlograms using hourly data of 28 rain gauge stations in the Keum river basin. From the results, we concluded as following; (1) Among three cases (Case A, Case B, Case C) considered, the Case A(+,+) seems to be the most relevant as it is not distorted much by zero measurements. (2) The spatial correlograms based on the lognormal distribution, which is theoretically as well as practically adequate, is better than that based on the Gaussian distribution. (3) The spatial correlation in July exponentially decrease more obviously than those in other months. (4) The spatial correlograms should be derived considering the temporal resolution(hourly, daily, etc) of interest.

• The Journal of Engineering Geology
• /
• v.32 no.1
• /
• pp.157-171
• /
• 2022

Electrical resistivity tomography (ERT) is a traditional and representative geophysical method for determining the resistivity distributions of surrounding soil and rock volumes. Depth resolution profiles and sensitivity distribution sections of the resistivities with respect to various electrode configurations are calculated and investigated using numerical model data. Shallow vertical resolution decreases in the order of Wenner, Schlumberger, and dipole-dipole arrays. A high investigable depth in homogeneous medium is calculated to be 0.11-0.19 times the active electrode spacing, but is counterbalanced by a low vertical resolution. For the application of ERT depth resolution profiles and sensitivity distributions, we provide subsurface structure models for two types of land-creping failure (planar and curved), subvertical fracture, and weathered layer over felsic and mafic igneous rocks. The dipole-dipole configuration appears to be most effective for mapping land-creeping failure planes (especially for curved planes), whereas the Wenner array gives the best resolution of soil horizons and shallow structures in the weathered zone.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.4
• /
• pp.299-308
• /
• 2001

We examined the growth variation with water depth, interval between suspended lines and locality of seedling production of sea squirt. Halocpthia roretzi, measuring approximately $10.1\~15.3$ mm in tunic height, was cultured at the farm near Guryongpo, Pohang city from 7 January to 6 December 1998 (333 days). Growth condition depending on culture depth was most favourable at the depth of $10\~12$m, It was concluded that nutritional conditions were better at the depth since there was a greater mount of phytoplankton than at any other depth in the water column. Growth condition depending on distance between suspended lines was most favourable at the interval of 2 m and 2.5 m than at the interval of t m and 1.5 m, There was no significance difference in growth variation with locality of seedling. The seasonal variations in growth of tunic height, meat and total weight were correlated with temperature and chlorophyll a, In the depth of $10\~12m$ the rate of increase in tunic height was generally greatest in the growth period II ($244{\mu}m/day$) and IV ($338{\mu}m/day$), lower in the period I ($108{\mu}m/day$), and slightly increased during the period III ($185{\mu}m/day$). The water column have showed a typical seasonal pattern with temperature ranged between $12.07{\sim}24.14^{\circ}C$ and over $20^{\circ}C$ between July and September.

• Korean Journal of Animal Reproduction
• /
• v.26 no.3
• /
• pp.291-298
• /
• 2002

This study was carried out to investigate the reproductive status and the effect of progesterone treatment on the recovery of reproductive disorders in Hanwoo. Hanwoo farms were surveyed the general management status, such as the type of barn, the feed intake, the incidence of reproductive disorders. The reproductive disorder cattle were treated 7 days insertion of control internal drug releasing for cattle (CIDR) and injection of PGF$_2$$\alpha$ at 1 day before removal. The recovery of reproductive disorders was assessed by determining the pregnancy following artificial insemination. The total number of surveyed Hanwoo farms was 127, and the total incidence rate of reproductive disorders was 19.7% (209/1,061). Compared to the herd size, the incidence rates of reproductive disorders in less than 10 heads (37.5%) was significantly (P<0.05) higher than in 10 to 20 heads (14.7%) and more than 20 heads (13.6%) of herd size per farm. The incidence rate of reproductive disorders in tie stall barn was significantly (P<0.05) higher than in free stall barn (30.4% vs. 14.7%), and even in free stall barn, that tended to decrease as the floor area was larger. The incidence rate of reproductive disorder by the parity was highest in heifer (50.7%), and that tended to decrease as the parity was increased. The distribution rate of the case of reproductive disorder in anestrus, recovery rate of reproductive disorders fellowing CIDR treatment was 75.1% (157/209). In the recovery rate of reproductive disorders by body condition score (BCS), BCS 1, 2 and 3 was significantly (P<0.05) higher pregnancy rate (85.7, 84.9 and 86.8%), and gross recovery rate in emaciated cattle was better than in obese cattle (BCS 4, 5). In conclusion, the incidence rate of reproductive disorders in Hanwoo raised in Youngju province area was 19.7%, and that tended to decrease as the herd size was increase because of increased farmer's attentions, and the floor area was larger. The majority of the case of reproductive disorders was anestrus. The recovery rate of reproductive disorders following CIDR treatment was 75.1%, and to optimize the recovery rate of reproductive disorders, cows and heifers were maintained BCS 1, 2 and 3 by moderate management.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.36 no.5
• /
• pp.757-767
• /
• 2016

The power spectral density (PSD) for the road surface roughness on the bridges of minor roads in Wonju city and Hoengseong-gun, Gangwon-do is presented. To obtain the PSD, the road surface roughness on 18 different bridges with various superstructure type and span is measured by GPS at every 10 to 30cm interval. Assuming the PSD as the stationary normal probability process with zero mean value, the PSD of measured road surface roughness is obtained by applying the Maximum Entropy Method (MEM). A simple formula in evaluating the PSD of RC slab bridge, Rahmen bridge and PSC I-girder bridge which is applicable to the dynamic response analysis of bridges considering the road surface roughness is proposed. Using the calculated PSD curves, the road surface conditions on the 18 bridges are evaluated. The statistical relationship between the PSD and the IRI is presented by applying linear regression and correlation analysis.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.40 no.5
• /
• pp.574-579
• /
• 1995

To investigate the effect of the midsummer drainage method on growth and lodging characters, Dongjinbyeo was direct seeded on dry paddy field under 4cm of soil depth at May 1 by seeding machine. Three kind of drainage methods were treated such as, once in 20day, towice in 20, 30 days and 3 times 20, 30, 40 days after flooding. As increase the drainage times, the culm and internode length were shorter, culm wall of 4th internode was thicker, breaking weight was heavier, height of center weight was lower, lodging index was reduced, and dry weight of root was increased. Field lodging occured seriously at none drainage but didn't, with two or three times of drainage. Grain yield was not shown significantly different compared with constant flooding irrespective of midsummer drainage times. Therefore two or three times of midsummer drainage could be recommended as the effective water management for the reduction of lodging occurance in direct seeding culture on dry paddy field.

• Economic and Environmental Geology
• /
• v.36 no.6
• /
• pp.501-510
• /
• 2003

Several geophysical surveys(electrical resistivity, electromagnetic, seismic refraction, CPR) were conducted to primarily investigate the gallery and the geomembrane at an abandoned mine(Imcheon mine). The subsurface structure mapped from seismic refraction survey mainly consists of three velocity layers(>1000 m/s, 1000∼2000 m/s,＜2000 m/s). Top of the bedrock, whose velocities exceed 2000 m/s, appears to be at depth of 7.5∼10m. Higher resistivities (of ten thousands-hundred of thousands ohm-m) are interpreted to be associated with a open(cavities) gallery. The events at depth of approximately 0.5∼0.7m in GPR sections are probably caused by high-density-poly-ethylene geomembrane. Taking into consideration of the differences in the spatial resolution between georadar and electrical surveys, the events of geomembrane correspond to the top of the high resistivities at depth of about 2m. The segments, characterized with the higher conductivities in the electromagnetic data and the lower resistivities in the electrical resistivity data, are probably associated with surface water or tear zone of geomembrane.

• Journal of the Korea Concrete Institute
• /
• v.26 no.6
• /
• pp.771-778
• /
• 2014

This paper concerns the flexural behavior of hybrid steel fiber-reinforced ultra high performance concrete (UHPC) beams. It presents experimental research results of hybrid steel fiber-reinforced UHPC with steel fiber content of 1.5% by volume and steel reinforcement ratio of less than 0.02. This study aims at providing realistic information about UHPC beams in bending in order to establish a reasonable prediction model for flexural resistance in structural code in the future. The experimental results show that hybrid steel fiber-reinforced UHPC is in favor of cracking resistance and ductility of beams. The ductility indices range through 9.2 to 15.2, which means high ductility of UHPC. Also, the flexural capacity of beam which contains stirrups in pure bending zone is similar to that of beam which does not contain stirrups in pure bending zone. This result represents that the flexural capacity is not affected by the presence of stirrups whose spacing is 150 mm in bending zone.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.12
• /
• pp.2311-2318
• /
• 2007

Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. Accurate predictions of software release times, and estimation of the reliability and availability of a software product require Release times of a critical element of the software testing process : test coverage. This model called Enhanced non-homogeneous Poission process(ENHPP). In this paper, exponential coverage and S-shaped model was reviewed, proposes the Kappa coverage model, which make out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on SSE statistics and Kolmogorov distance, for the sake of efficient model, was employed. Numerical examples using real data set for the sake of proposing Kappa coverage model was employed. This analysis of failure data compared with the Kappaa coverage model and the existing model(using arithmetic and Laplace trend tests, bias tests) is presented.