• Dementia and Neurocognitive Disorders
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• v.22 no.4
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• pp.148-157
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• 2023

Background and Purpose: Episodic memory is a system that receives and stores information about temporally dated episodes and their interrelations. Our study aimed to investigate the relevance of episodic memory to time perception, with a specific focus on simultaneity/order judgment. Methods: Experiment 1 employed the simultaneity judgment task to discern differences in time perception between patients with mild cognitive impairment or dementia, and age-matched normals. A mathematical analysis capable of estimating subjects' time processing was utilized to identify the sensory and decisional components of temporal order and simultaneity judgment. Experiment 2 examined how differences in temporal perception relate to performance in temporal order memory, in which time delays play a critical role. Results: The temporal decision windows for both temporal order and simultaneity judgments exhibited marginal differences between patients with episodic memory impairment, and their healthy counterparts (p = 0.15, t(22) = 1.34). These temporal decision windows may be linked to the temporal separation of events in episodic memory (Pearson's ρ = -0.53, p = 0.05). Conclusions: Based on our findings, the frequency of visual events accumulated and encoded in the working memory system in the patients' and normal group appears to be approximately (5.7 and 11.2) Hz, respectively. According to the internal clock model, a lower frequency of event pulses tends to result in underestimation of event duration, which phenomenon might be linked to the observed time distortions in patients with dementia.

• Journal of Korea Water Resources Association
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• v.55 no.10
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• pp.737-748
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• 2022

Due to the lack of flood data, the water engineering practice calculates the design flood using rainfall frequency analysis and rainfall-runoff model. However, the rainfall frequency analysis for arbitrary duration does not reflect the regional characteristics of the duration and amount of storm event. This study proposed a practical method to calculate the design flood in a watershed considering the characteristics of storm event, based on the bivariate rainfall frequency analysis. After extracting independent storm events for the Pyeongchang River basin and the upper Namhangang River basin, we performed the bivariate rainfall frequency analysis to determine the design storm events of various return periods, and calculated the design floods using the HEC-1 model. We compared the design floods based on the bivariate rainfall frequency analysis (DF_BRFA) with those estimated by the flood frequency analysis (DF_FFA), and those estimated by the HEC-1 with the univariate rainfall frequency analysis (DF_URFA). In the case of the Pyeongchang River basin, except for the 100-year flood, the average error of the DF_BRFA was 11.6%, which was the closest to the DF_FFA. In the case of the Namhangang River basin, the average error of the DF_BRFA was about 10%, which was the most similar to the DF_FFA. As the return period increased, the DF_URFA was calculated to be much larger than the DF_FFA, whereas the BRFA produced smaller average error in the design flood than the URFA. When the proposed method is used to calculate design flood in an ungauged watershed, it is expected that the estimated design flood might be close to the actual DF_FFA. Thus, the design of the hydrological structures and water resource plans can be carried out economically and reasonably.

• Korean Journal of Construction Engineering and Management
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• v.8 no.1 s.35
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• pp.124-131
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• 2007

Project management means usually managing the rate of construction progress. But it also contains preparing scheme of execution and establishing plan for equipment, material, labor force to finish project within expected duration. In this paper to establish effective project planning a road pavement operation is selected as a case and simulation method is used for analyzing it. Next probability distributions are created after analyzing collected data and these are reflected in simulation model. Simulated result is compared with real project planning using models of lean concrete pavement process and concrete slab pavement process to verify efficiency of this model. In the event we know that project planning using simulation is more effective than one of the field in the aspects of duration and cost. Meanwhile simulated result in this paper has a limitation in accuracy because various constraints of filed are not reflected in it. However if we reflect this constraints in model through examining field in future this limitation is expected to be improved.

• Journal of Embryo Transfer
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• v.26 no.1
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• pp.85-89
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• 2011

Somatic cell nuclear transfer (SCNT) is a useful tool for reproducing genetically identical animals or producing transgenic animals. Many reports have demonstrated that the efficiency of animal cloning by SCNT requires reprogramming of the somatic nucleus to a totipotent like-state. The SCNT-related reprogramming might mimic the natural reprogramming process that occurs during normal mammalian development. However, recent evidence indicates that the reprogramming event by SCNT is incomplete. In this study, the traditional SCNT procedure (TNT) was modified by injecting donor nuclei into recipient cytoplasm prior to the enucleation process to expose the donor nucleus before removing the karyoplast containing the chromosomes of the oocytes which might possess additional reprogramming factors, and this modified technique was named as reversing the usual order of SCNT (RONT). Other procedures including activation and in vitro culture were the same as TNT. Contrary to expectations, the rate of blastocyst development was not different significantly between RONT and TNT (8.6% and 7.9%, respectively). However, duration of micromanipulation performed by the same technician and equipments was remarkably reduced because the ruptured oocytes after nuclear injection were excluded from the enucleation process. This study suggests that RONT, a simplified SCNT protocol, shortens the duration of SCNT procedure and this less time-costing protocol may enable the researchers to perform murine SCNT easier.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.229-244
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• 2002

The purpose of this study were a two-fold: (1) to analyze event and phase of handspring salto forward stretched with turn; (2) to know the differences in the kinematic variables between two groups. A Kwon3D program served for the estimation of this study. The group was divided into three National representative and three well-trained calisthenics in this study. The results of this study revealed that (1) the forward somersault performance was increased when duration time in the air was long during the salto forward stretched that the duration time of Handspring is short, the pressure at takeoff is high, the stride is large, and hands are supporting on the ground quickly; (2) comparing the angular movement of anterior and posterior y axis and vertical z axis, the angular movement of right and left $\times$ axis was higher during the performance. As a result, the national representative players showed better performance in Handspring salto forward stretched with turn.

• Water for future
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• v.28 no.5
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• pp.205-217
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• 1995

The historical data from 3, 550 event storms during 11 years in Wi-stream basin have been used to investigate the statistical parameter of the time distribution for design storms by the method of Yen-Chow, Huff, Pilgrim-Cordery and Mononobe. The dimensionless value of triangular hyetograph, $a^0$, ranges from 0.44 to 0.50 and trapezoidal hyetograph, $h^0$, value increases as the duration time is getting longer in Yen-Chow method. In the Huff, the second-quartile storms occurred most frequently and third-quartile storms occurred most infrequently. In the Pilgrim-Cordery, the shapes for shorter than 6-hour durations are advanced tendency. However, for longer than 6-hour durations show delayed tendency. In the Mononobe, every one hour rainfall occured Centered Type. The application of these methods for each duration time was tested by using the observed rainfall-runoff data of Wi-stream basin. As a result, the reappearance of hydrographs of triangular hyetograph by Yen-Chow method showed promising, and it was approved to be used for prediction of the ungaged basins.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.495-499
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• 2003

As an alternative to overcome the limitations of current popular schedule system such as Bar Chart, PERT, CPM in proving the feasibility of a given project schedule and duration, this research applies simulation to the 'Shiwha Techno-Valley project, and then reviews its usability in time management. Shiwha-Techno-Valley is a gigantic project requiring large number of equipment and resulting in traffic congestion. In particular, project site is located near the Shiwha industrial complex and Daeboo-Do tourist place. Therefore, current traffic needs should not be ignored. This research evaluates whether the project can be finished in a given time even if construction equipment increase in addition to the current traffic. Through the analysis of the simulation output, the research identifies the optimal resource input and the needs on alternative schedule for the project.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.77-85
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• 2009

In South Korea, seasonal, local and temporal climatic characteristics are variable in rainfall patterns. To design or assess the reliability of hydrosystem, information about the rainfall event under consideration is important. In this process, the complete description of a design storm involves the specification of rainfall duration, depth, and its temporal pattern. Generally, to use an appropriate temporal pattern for a design storm is of great importance in the design and evaluation of hydrological safety for hydrosystem. For purpose of selecting of factors affecting the occurrence of rainfall patterns, Huff's dimensionless method was executed and examined by statistical contingency tables analysis through which the inter-dependence of the occurrence frequency of rainfall patterns with respect to geographical location, rainfall duration and depth, and seasonality is investigated. This analysis result can be used to establish flood policies and to design or assess the reliability of hydrosystem.

• Korean Journal of Construction Engineering and Management
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• v.10 no.3
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• pp.102-110
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• 2009

Although several research efforts have been directed to fast-tracking to reduce the total delivery time, few researches have been studied on concurrent engineering in construction projects. The focus of fast-tracking is primarily on overlapping independent activity pairs. In comparison, the focus of concurrent engineering is on overlapping dependent activity pairs. Dependent activities are much harder to overlap successfully. This paper presents a simulation-based Concurrent Engineering methodology to optimize the overall duration of a set of design activities in a project by modelling key factors that determine the duration of individual activities and overlap between dependent activities. This methodology involves determining how much to overlap activities, how to decide which activities to overlap and the corresponding cost and time tradeoffs using a discrete event model solution. This simulation model, therefore, can be used as a reference on decision-making to define optimum point between time and cost.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.3
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• pp.313-324
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• 2013

It is widely known that untreated Combined Sewer Overflows (CSOs) that directly discharged from receiving water have a negative impact. Recent concerns on the CSO problem have produced several large scale constructions of treatment facilities, but the facilities are normally designed under empirical design criteria. In this study, several criteria for defining CSOs (e.g. determination of effective rainfall, sampling time, minimum duration of data used for rainfall-runoff simulation and so on) were investigated. Then this study suggested a standard methodology for the CSO calculation and support formalized standard on the design criteria for CSO facilities. Criteria decided for an effective rainfall was over 0.5 mm of total rainfall depth and at least 4 hours should be exist between two different events. An Antecedent dry weather period prior to storm event to satisfy the effective rainfall criteria was over 3 days. Sampling time for the rainfall-runoff model simulation was suggested as 1 hour. A duration of long-term simulation CSO overflow and frequency calculation should be at least recent 10 year data. A Management plan for the CSOs should be established under a phase-in of the plan. That should reflect site-specific conditions of different catchments, and formalized criteria for defining CSOs should be used to examine the management plans.