• Journal of KIISE:Databases
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• v.33 no.2
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• pp.201-213
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• 2006

A time-series database is a set of time-series data sequences, each of which is a list of changing values of the object in a given period of time. Subsequence matching is an operation that searches for such data subsequences whose changing patterns are similar to a query sequence from a time-series database. This paper addresses a performance issue of time-series subsequence matching. First, we quantitatively examine the performance degradation caused by the window size effect, and then show that the performance of subsequence matching with a single index is not satisfactory in real applications. We argue that index interpolation is fairly useful to resolve this problem. The index interpolation performs subsequence matching by selecting the most appropriate one from multiple indexes built on windows of their inherent sizes. For index interpolation, we first decide the sites of windows for multiple indexes to be built. In this paper, we solve the problem of selecting optimal window sizes in the perspective of physical database design. For this, given a set of query sequences to be peformed in a target time-series database and a set of window sizes for building multiple indexes, we devise a formula that estimates the cost of all the subsequence matchings. Based on this formula, we propose an algorithm that determines the optimal window sizes for maximizing the performance of entire subsequence matchings. We formally Prove the optimality as well as the effectiveness of the algorithm. Finally, we perform a series of extensive experiments with a real-life stock data set and a large volume of a synthetic data set. The results reveal that the proposed approach improves the previous one by 1.5 to 7.8 times.

• Journal of Biosystems Engineering
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• v.20 no.2
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• pp.162-172
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• 1995

The ventilation in greenhouse have been important for such as adjustment of temperature, supplying of the oxygen, prevention of the overhumidity, density adjustment of $CO_2$, discharge of harmfulness gas, etc. However, the general ventilation which had been used the quantitative control method in discharge of a property of air mechanism in greenhouse, and caused mainly in waste of the heating energy and growth obstacle of the vegetable. Therefore, this study was peformed to obtain more scientific ventilation method using by analysis and measurement of the isothermal lines according to opening of window ventilation in greenhouse, and the results are summarized as follows. 1. The ventilating amount was more influenced by rather opening amount of window than the ventilating time. 2. In window ventilation, the temperature in greenhouse was mostly changed within 5 minutes after ventilating not regard to the spot of opening, after about 10 minutes temperature became to equilibrium state under the respective ventilating conditions. 3. In opening of the skylight only, isothermal lines were complicated, therefore, a tall vegetable may be possible to damage by a cold-weather from the lower central port in greenhouse. 4. Isothermal lines were a tendency to simply in opening of a side window that may be more effective ventilation in kinds of the short vegetable. 5. In conditions of internal temperature>setting temperature>external temperature, a skylight can be suitable to open 10~20cm in order to the optimum ventilation in greenhouse. 6. In conditions of internal temperature>external temperature>setting temperature, opening of all the windows or both the side windows that can be suitable in order to obtain the optimum ventilation in greenhouse. 7. An effect of ventilation was the most excellent to open of all the windows or both the side windows, and it were also found orderly excellent to open of the side window and the skylight or the skylight only, to open of the side window only. 8. Temperature was varied as the equation of T=Tc+ (To-Tc)e-at, and the ranges of (a) values were limited within 0.34~0.68. 9. A variations of humidity were similar to that of temperature, s.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.11
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• pp.25-34
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• 2019

It is important to design windows in a reasonable way considering the performance characteristics of the elements of the window rather than just to increase the thermal energy performance of the window. In this study, the Heat-transfer Coefficient as insulation performance of the windows and together with the grade of the glass's SHGC (Solar Heat Gain Coefficient) were analyzed to relate to the energy efficiency performance of the building by azimuth angle. Based on this basic study, the Heat-transfer Coefficient of windows and the SHGC rating of glass were applied to the unit plan of apartment building, and the Heating and Cooling Demand were analyzed by azimuth angle. Apartment plan types were divided into 2 types of Non-extension and extension of balcony. The designPH analysis data derived from the variant of the Heat-transfer Coefficient and SHGC, were put into PHPP(Passive House Planning Package) to analyze precisely the energy efficiency(Heating and Cooling Demands) of the building by azimuth angle. In addition, assuming the 'ㅁ' shape layout, energy efficiency performance and potential of PV Panel installation also were analyzed by floors and azimuth angle, reflecting the shading effects by surrounding buildings. As the results of the study, the effect of Heat Gain by SHGC was greater than Heat Loss due to the Heat-transfer Coefficient. So it is more effective to increase SHGC to satisfy the same Heating Demand, and increasing SHGC made possible to design windows with low Heat-transfer Coefficient. It was also revealed that the difference in annual Heating and Cooling Demands between the low, mid and high floor households is significantly high. In addition to it, the installation of PV Panel in the form of a shading canopy over the window reduces the Cooling Load while at the same time producing electricity, and also confirmed that absolute thermal energy efficiency could not be maximized without controlling the thermal bridge and ventilation problems as important heat loss factors.

• Journal of Family Resource Management and Policy Review
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• v.17 no.1
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• pp.1-18
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• 2013

This study grasps the living condition of Single-Parent-Family, and compares Single-Parent-Family with Dual-Parent-Family to analyze necessary factors to enjoy the happier life. The data from '2009 the Korean Time Use Survey' and '2010 the National Survey of Korean Families(NSKF)' are used for this study. ANOVA, Duncan test, Correlation Analysis(SPSS for windows, Ver. 18.0) are used for statistical method. Here are the results of this study. First, distribution of living-time-usage of the Single-Parent-Family is different from that of Dual-Parent-Family. Second, the difference in the amount of leisure time, time distribution, and the content of activity was observed based on the gender of Single-Parent-Family. Third, there is a difference in family leisure activity time among Dual-Parent-Family, Mother-Single-Parent-Family, and Father-Single-Parent-Family in holidays. Fourth, there is a clear difference between Dual-Parent-Family and Single-Parent-Family, after looking at life satisfaction degree in work-family-leisure life experience.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.167-179
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• 2001

This paper discusses an index-based subsequence matching that supports time warping in large sequence databases. Time warping enables finding sequences with similar patterns even when they are of different lengths. In earlier work, we suggested an efficient method for whole matching under time warping. This method constructs a multidimensional index on a set of feature vectors, which are invariant to time warping, from data sequences. For filtering at feature space, it also applies a lower-bound function, which consistently underestimates the time warping distance as well as satisfies the triangular inequality. In this paper, we incorporate the prefix-querying approach based on sliding windows into the earlier approach. For indexing, we extract a feature vector from every subsequence inside a sliding window and construct a multi-dimensional index using a feature vector as indexing attributes. For query precessing, we perform a series of index searches using the feature vectors of qualifying query prefixes. Our approach provides effective and scalable subsequence matching even with a large volume of a database. We also prove that our approach does not incur false dismissal. To verily the superiority of our method, we perform extensive experiments. The results reseal that our method achieves significant speedup with real-world S&P 500 stock data and with very large synthetic data.

• Journal of Biosystems Engineering
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• v.29 no.6 s.107
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• pp.515-520
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• 2004

A device far estimating the optimal artificial insemination time consisted of a computer, RS module, and six direct-reflex photo-sensors. Program was written in LabWindows CVI. In order to establish references for estimating optimal artificial insemination time, lying rate of the thirty three $Berkshire{\times}Hampshire crossbred sows (parity 5 to 6) was recorded from 2 days after moving into stalls to artificial insemination using a time lapse VCR and was measured every hour with one minute interval using the scan point sampling method. Twenty low hours in a day were divided into three comparing periods : 21:00 to 06:59, 07:00 to 13:59, and 14:00 to 20:59. If sum of the percentages of tying during a comparing period was less than the reference value, the starting hour of the comparing period was considered as onset of estrus and the optimal artificial insemination time was estimated at 20 to 24 hours after onset of estrus. The experimental device was evaluated with twenty five $Berkshire{\times}Hampshire$ crossbred sows (parity 2 to 7) and 23 of 25 sows $(92\%)$ were pregnant. This result suggests that the experimental device is excellent in performance for estimating optimal artificial insemination time.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.179-187
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• 2020

This paper investigates the construction equipment accidents by time. Construction sites are unique with many different hazardous conditions which cause accidents. According to the Occupational Safety and Health Administration (OSHA), accidents related to construction equipment are one of the most leading causes of fatal injuries in the construction industry. While there have been many studies investigating the equipment-related accidents, few research studies provided in-depth analyses about the time that accidents frequently occurred. By using the OSHA accidents data collected between 1997 and 2012, this paper analyzed the accidents data by time, equipment type including excavator, backhoe, dozer, and crane, accident cause, and injury class. The analyses revealed that the time window with most accidents was between 13:00 and 13:59. In terms of the injury class, the time windows with the highest numbers of equipment accidents were between 13:00 and 13:59 and between 11:00 and 11:59 for fatality and hospitalization, respectively. For the accident causes, equipment operator's error was the highest number of accident causes. It is expected that findings from the analyses can be used to more strategically develop management plans and guidelines to prevent accidents related to construction equipment to practitioners.

• The KIPS Transactions:PartC
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• v.16C no.4
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• pp.477-486
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• 2009

This paper proposes a dynamic bandwidth allocation (DBA) algorithm with adaptive maximum transmission window (DBA-AMTW) to increase channel utilization in Ethernet passive optical networks (EPONs). A polling mechanism in EPON determines channel utilization and puts constraints on DBA algorithm and scheduling. DBA algorithms based on interleaved polling with stop (IPS) allocate transmission windows to optical network units (ONU) considering requests of all ONUs. However channel idle time when any ONU does not transmit packets decreases channel utilization. Proposed DBA-AMTW improves efficiency of a network and allocates transmission windows effectively by appropriate DBA computation from REPORT messages of all ONUs. An adaptive maximum transmission window for each ONU determined by a DBA computation in the previous scheduling cycle. Simulation results show that the proposed DBA algorithm improves performance of throughput and average delay time.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.38-43
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• 2015

This paper describes a GPS signal generator that can generate multiple satellite signals in real time at the RF level. It realizes the verified software algorithm on a FPGA. The algorithm models orbits and environmental errors such as ionospheric and tropospheric multipath. The position of a simulated receiver is one of simulation parameters. The hardware which consists of a digital logic board and an analog board can generate 16 simulated satellites signals at the same time. The users can generate spoofing signals and jamming signals as well as satellite signals by using the windows-based control software. In addition, the software provides GIS-based simulation scenarios editing tools. We verified the generator by using commercial receivers. As an application, we configured generators as indoor positioning systems and tested them in a building. To improve the accuracy of indoor systems is our further study.

• Journal of Intelligence and Information Systems
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• v.13 no.1
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• pp.49-58
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• 2007

MDPDPTW (Multi-Depot Pickup and Delivery Problem with Time Windows) is a typical model among the optimization models based on the pickup and delivery flow in supply chains. It is based on multi-vehicles in multi-depots and does not consider moving vehicles near pickup and delivery locations. In ubiquitous environments, it is possible to obtain information on moving vehicles and their baggage. Providing the proper context from the perspective of moving vehicles and their baggage allows for more effective vehicle routings. This study proposes Integer Programming-based MDPDPTW including the information on moving vehicles and their baggage in a ubiquitous environment: u-MDPDPTW, and shows the viability and effectiveness of u-MDPDPTW through comparative experiments of MDPDPTW and u-MDPDPTW.