• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.91-101
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• 2014

In this study, we presented a timing verification method for a passenger car diesel engine management system (EMS) using measurement-based worst-case execution time (WCET) analysis. In order to cope with AUTOSAR-compliant software architecture, a development process model is proposed. In the process model, a runnable is regarded as a test unit and its temporal behavior (i.e. maximum observed execution time, MOET) is obtained along with on-target functionality evaluation results during online unit test. Furthermore, a cost-effective framework for online unit test is proposed. Because the runtime environment layer and the standard calibration environment are utilized to implement test interface, additional resource consumption of the target processor is minimized. Using the proposed development process model and unit test framework, the MOETs of 86 runnables for diesel EMS are obtained with 213 unit test cases. Using the obtained MOETs of runnables, the WCETs of tasks are estimated and the schedulability is evaluated. From the schedulability analysis results, the problems of the initially designed schedule table is recognized and it is fixed by redesigning of the runnable mapping and task offset. Through the various test scenarios, the proposed method is validated.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.503-510
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• 2015

The objective of this study is to analyze the investment adequacy of the projects implemented according to the master plan on sewerage rehabilitation at Seoul. The planned and actually implemented ratio of invested money on sewage treatment plants (STPs) to sewers were compared in two temporal periods. Though the planned ratio of investment on STPs to sewers was 50:50 (in 2009-2020), the actual implemented ratio in 2009-2013 was 34:66. Until 2020, the greater investment ratio on STPs to sewers should be made considering the necessity of coping with stricter legal compliance on advanced treatment, stormwater treatment and so on. The priority of the planned and partially implemented projects among four STPs and at each STP was evaluated. Considering only the performance indicator of reduced load of BOD, T-N, T-P per the capacity of each STP facility, the performance among four STPs was shown as Jung-Rang>Tan-Cheon>Seo-Nam>Nan-Ji. The reverse order of the performance results in the past may be considered for future investment priority, but the efficiency of operation implemented at each STP, deteriorated status of each STP, investment in the past and so forth should also be considered. As for the priority of projects conducted within each STP, projects related to legal compliance (such as advanced tertiary treatment, stormwater treatment, etc.) have highest priority. Odor-related project and inhabitant-friendly facility related projects (such as building park on STPs, etc.) has lower priority than water quality related projects but interactivity with end-users of sewerage should also be important.

• Journal of Korea Water Resources Association
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• v.39 no.9 s.170
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• pp.767-777
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• 2006

The goal of this study is to improve Huff's method which is the most popular method for rainfall time distribution in Korea. As the first step, we reevaluated the context of Huff's original research motivations, geography and rainfall pattern of study area, and compared that to Korean situations. In original Huff's results, no change in temporal distribution characteristics were found for different rainfall durations. This was found to be different from Korean situations. Furthermore, results from the MOCT(Ministry of Construction and Transportation) version of Huff's method is on a gage basis not on a watershed basis, thus making it difficult to select cumulative rainfall curves representative of a watershed. In addition, all rainfall data regardless of their magnitude were used in the MOCT version of Huff' method which is different from original Huff's which screened out data by using a threshold value of 25.4mm. For both point and areal mean rainfall, time distribution characteristics of rainfall for various durations were found to be different. This was statistically proven by K-S test at 5% significance level as some cumulative rainfall curves developed from the rainfall data of certain durations were found to be not significant with cumulative rainfall curves developed from the rainfall data of all durations. Therefore, in order to apply Huff's method to Korean situations, it is recommended that dimensionless cumulative curve must be developed for various rainfall duration intervals using rainfall data greater than a certain threshold value.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.499-514
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• 2011

An underlying assumption of traditional hydrologic frequency analysis is that climate, and hence the frequency of hydrologic events, is stationary, or unchanging over time. Under stationary conditions, the distribution of the variable of interest is invariant to temporal translation. Water resources infrastructure planning and design, such as dams, levees, canals, bridges, and culverts, relies on an understanding of past conditions and projection of future conditions. But, Water managers have always known our world is inherently non-stationary, and they routinely deal with this in management and planning. The aim of this paper is to give a brief introduction to non-stationary extreme value analysis methods. In this paper, a non-stationary hydrologic frequency analysis approach is introduced in order to determine probability rainfall consider changing climate. The non-stationary statistical approach is based on the conditional Generalized Extreme Value(GEV) distribution and Maximum Likelihood parameter estimation. This method are applied to the annual maximum 24 hours-rainfall. The results show that the non-stationary GEV approach is suitable for determining probability rainfall for changing climate, sucha sa trend, Moreover, Non-stationary frequency analyzed using SOI(Southern Oscillation Index) of ENSO(El Nino Southern Oscillation).

• Journal of Korea Water Resources Association
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• v.40 no.8
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• pp.601-615
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• 2007

A selective withdrawal method has been widely used to control the quality of water released from a stratified reservoir and to improve downstream ecosystem habitats. Recently, several existing reservoir withdrawal facilities have been modified to accommodate multi-level water intake capabilities in order to adapt the impact of long-term discharge of high turbidity flow. The purpose of this study was to assess the effect of selective withdrawal method on the control of downstream turbidity and its impact on water quality in Daecheong Reservoir. A laterally integrated two-dimensional hydrodynamic and eutrophication model, which was calibrated and validated in the previous studies, was applied to simulate the temporal variations of outflow turbidity with various hypothetical selective withdrawal scenarios. In addition, their impacts on the algal growth as well as water quality constituents were analyzed in three different spatial domains of the reservoir The results showed that the costly selective withdrawal method would provide very limited benefits for downstream turbidity control during two years of consecutive simulations for 2004-2005. In particular, an excessive withdrawal from the epilimnion zone for supplying upper layer clean water resulted in movement of turbidity plume that contained high phosphorus concentrations upward photic zone, and in turn increased algal growth in the lacustrine zone.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.6
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• pp.1094-1103
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• 2001

According to standard procedures as defined in the users handbook for sea level data processes, I was compared to Topex/Poseidon sea level data from the first 350days of mission and Tide Gauge sea level data from the Amsterdam- Crozet- Kerguelen region in the South Indian Ocean. The comparison improves significantly when many factors for the corrections were removed, then only the aliased oceanic tidal energy is removed by oceanic tide model(11) in this period. Making the corrections and smoothing the sea level data ()ver 60km along-track segments and the Tide Gauge sea level data for the time series results in the digital correlation and RMS difference between the two data of c=-0.12 and rms= 11.4cm, c=0.55 and rms=5.38cm, c=0.83 and rms=2.83cm, and c=0.24 and rms=6.72 for the Amsterdam, Crozet and Kerguelenplateau, and Kerguelen coast, respectively. It was also found that the Kerguelen plateau has a comparisons due to propagating signals(the baroclinic Rossby wave with velocity of -3.9 ~-4.2cm/sec, period of 167days and amplitude of 10cm) that introduce temporal lags(${\gamma}$: 10~30days) between the altimeter and tide gauge time series. The conclusion is that on timescales longer than about 10days the RMS sea level errors are less than or of the order of several centimeters and are mainly due to the effects of currents rather than the effects of stories(water temperature, density) and winds.

• Ocean and Polar Research
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• v.28 no.2
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• pp.79-94
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• 2006

Spatio-temporal patterns in the zooplankton communities, physicochemical environmental factors, and dominant species were examined in Camak Bay from April, July, September, and November, 2003. A total of 40 taxa were sampled with a mean abundance of total zooplankton ranging from $270{\sim}1,803inds/m^3$. The most abundant species was Acartia erythraea, followed by Eurytemora pacifica, Podon polyphemoides, A. omorii, and Paracalanus parvus s. 1 during the study period. Multivariate analysis revealed significant differences in community structure among three regions: the middle part of the sampling area (B), sites 1, 2 (A) and other sites (C). The number of species and diversity (H') varied significantly among the three regions (p<0.05), but no differences in the mean abundances were observed (p>0.05). In order to investigate factors affecting the correlations between the abundance of dominant species, all zooplankton and environmental factors ware calculated using a correlation analysis. Of these, the abundance of dominant taxon showed positive correlation with seawater temperature, salinity and dissolved oxygen (p<0.05). In statistical analysis showed that the environmental factors influencing the variation of the communities ere predominantly temperature, salinity, and dissolved oxygen.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.825-840
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• 2015

Adaptive bitrate (ABR) streaming technology has become an important and prevalent feature in many multimedia delivery systems, with content providers such as Netflix and Amazon using ABR streaming to increase bandwidth efficiency and provide the maximum user experience when channel conditions are not ideal. Where such systems could see improvement is in the delivery of live video with a closed loop cognitive control of video encoding. In this paper, we present streaming camera system which provides spatially and temporally adaptive video streams, learning the user's preferences in order to make intelligent scaling decisions. The system employs a hardware based H.264/AVC encoder for video compression. The encoding parameters can be configured by the user or by the cognitive system on behalf of the user when the bandwidth changes. A cognitive video client developed in this study learns the user's preferences(i.e. video size over frame rate) over time and intelligently adapts encoding parameters when the channel conditions change. It has been demonstrated that the cognitive decision system developed has the ability to control video bandwidth by altering the spatial and temporal resolution, as well as the ability to make scaling decisions.

• Clinical and Experimental Pediatrics
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• v.56 no.1
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• pp.26-31
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• 2013

Purpose: Lymphocyte subset recovery is an important factor that determines the success of hematopoietic stem cell transplantation (HSCT). Temporal differences in the recovery of lymphocyte subsets and the factors influencing this recovery are important variables that affect a patient's posttransplant immune reconstitution, and therefore require investigation. Methods: The time taken to achieve lymphocyte subset recovery and the factors influencing this recovery were investigated in 59 children who had undergone HSCT at the Department of Pediatrics, The Catholic University of Korea Seoul St. Mary's Hospital, and who had an uneventful follow-up period of at least 1 year. Analyses were carried out at 3 and 12 months post-transplant. An additional study was performed 1 month post-transplant to evaluate natural killer (NK) cell recovery. The impact of pre- and post-transplant variables, including diagnosis of Epstein-Barr virus (EBV) DNAemia posttransplant, on lymphocyte recovery was evaluated. Results: The lymphocyte subsets recovered in the following order: NK cells, cytotoxic T cells, B cells, and helper T cells. At 1 month post-transplant, acute graft-versus-host disease was found to contribute significantly to the delay of $CD16^+/56^+$ cell recovery. Younger patients showed delayed recovery of both $CD3^+/CD8^+$ and $CD19^+$ cells. EBV DNAemia had a deleterious impact on the recovery of both $CD3^+$ and $CD3^+/CD4^+$ lymphocytes at 1 year post-transplant. Conclusion: In our pediatric allogeneic HSCT cohort, helper T cells were the last subset to recover. Younger age and EBV DNAemia had a negative impact on the post-transplant recovery of T cells and B cells.

• Korean Journal of Remote Sensing
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• v.30 no.4
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• pp.431-444
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• 2014

As applications of spaceborne SAR imagery are extended, there are increased demands for accurate registrations for better understanding and fusion of radar images. It becomes common to adopt multi-resolution SAR images to apply for wide area reconnaissance. Geometric correction of the SAR images can be performed by using satellite orbit and attitude information. However, the inherent errors of the SAR sensor's attitude and ground geographical data tend to cause geometric errors in the produced SAR image. These errors should be corrected when the SAR images are applied for multi-temporal analysis, change detection applications and image fusion with other sensor images. The undesirable ground registration errors can be corrected with respect to the true ground control points in order to produce complete SAR products. Speeded Up Robust Feature (SURF) technique is an efficient algorithm to extract ground control points from images but is considered to be inappropriate to apply to SAR images due to high speckle noises. In this paper, an attempt is made to apply SURF algorithm to SAR images for image registration and fusion. Matched points are extracted with respect to the varying parameters of Hessian and SURF matching thresholds, and the performance is analyzed by measuring the imaging matching accuracies. A number of performance measures concerning image registration are suggested to validate the use of SURF for spaceborne SAR images. Various simulations methodologies are suggested the validate the use of SURF for the geometric correction and image registrations and it is shown that a good choice of input parameters to the SURF algorithm should be made to apply for the spaceborne SAR images of moderate resolutions.