7,352 research outputs found
The Importance of Change Management after ERP Implementation: An Information Capability Perspective
When firms implement enterprise resource planning, they need to redesign their business processes to make information flow smooth within organizations. ERP thus results in changes in processes and responsibilities. Firms cannot realize expected returns from ERP investments unless these changes are effectively managed after ERP systems are put into operation. This research proposes a conceptual framework to highlight the importance of the change management after firms implement ERP systems. Our research model is empirically tested using data collected from over 170 firms that had used ERP systems for more than one year. Our analysis reveals that the eventual success of ERP systems depends on effective change management after ERP implementation, supporting the existence of the valley of despair
A Study on water shut off period and countermeasure for effective water supply maintenance
Thesis(Master) -- KDI School: Master of Public Management, 2022Since the 1960s, Korea''s water supply has been rapidly expanded through state-led facility investment along with economic development, with 99.4% of the people receiving water supply services as of 2020. Korea''s water supply has reached the world''s highest level in terms of facility capacity and supply rate, but as of 2020, 34.8% of Korea''s buried water pipes have passed more than 20 years and their performance is rapidly decreasing.
In 2019, 630,000 citizens were damaged by the supply of discolored tap water for up to 67 days due to inappropriate work procedures, and waterworks business operators suffered more than KRW 6.6 billion in financial losses due to compensation for citizens'' damage. It is time to pay attention to maintenance to preserve stable functions so that this situation does not occur again, and the Ministry of Environment recently enacted ‘Detailed Standards for Maintenance of Waterworks Network Facilities’ to require water supply businesses to conduct regular water pipe cleaning. However, like other maintenance tasks such as emergency construction and altering waterworks system, cleaning of water pipes will cause shut off of tap water supply unless it is under special conditions such as double track supply.
Accordingly, measures to improve the efficiency of maintenance work and reduce citizens'' inconvenience were investigated through interviews with experts in consideration of loss, such as civil inconvenience, and benefits from regular maintenance of water facilities. Based on the experience of experts, the results of analyzing the optimal time and interval for maintenance work to the level of dissatisfaction of citizens according to water shut-off and finding out promotional and support measures to minimize dissatisfaction in the event of water shut off are as follows.
f there is sufficient prior notification of water shut off, citizens should not sensitively complain of discomfort until the water shut off duration of 12 hours and should perform it during late night time (23:00-05:00) when water consumption is low. In addition, detailed work schedules for each time period should be established in consideration of citizen inconvenience such as noise from excavation work at night, and maintenance work needs to be carefully planned at intervals of at least one month to prevent citizen inconvenience caused by repeated water shut-off. As a way to minimize inconvenience to citizens in the event of water shut-off, it is most important to notify citizens in advance, and it is desirable to notify them about a week in advance by various ways, such as sending individual SMS and posting banners. On the other hand, frequent guidance should not cause inconvenience to citizens due to the burden of fatigue. In addition, it was suggested that if water shut-off is to be carried out for a long time, a plan to support bottled water and water-tank trucks to be provided to the victims should also be set up.1. Introduction
2. Literature review.
3. Research questions and method
4. Research results.
5. Policy or Administrative Recommendations
6. ConclusionmasterpublishedSeung-Ho LE
The Light and Period Variations of the Eclipsing Binary AA Ursae Majoris
We present new multiband CCD photometry for AA UMa made on 8 nights between
January and March 2009; the light curves are the first ever compiled.
Historical light curves, as well as ours, display partial eclipses and inverse
O'Connell effects with Max I fainter than Max II. Among possible spot models, a
cool spot on either of the component stars and its variability with time permit
good light-curve representations for the system. A total of 194 eclipse timings
over 81 yrs, including our five timings, were used for ephemeris computations.
We found that the orbital period of the system has varied due to a periodic
oscillation overlaid on an upward parabolic variation. The continuous period
increase at a fractional rate of 1.310 is consistent with
that calculated from the W-D code and can be interpreted as a thermal mass
transfer from the less to the more massive secondary star at a rate of
6.610 M yr. The periodic component is in
satisfactory accord with a light-time effect due to an unseen companion with a
period of 28.2 yrs, a semi-amplitude of 0.007 d, and a minimum mass of =0.25 but this period variation could also arise from
magnetic activity.Comment: 23 pages, including 5 figures and 8 tables, accepted for publication
in PAS
Reproducing Field Measurements Using Scaled-Down Hydraulic Model Studies in a Laboratory
Little efforts have been made to the value of laboratory model study in closing the gap between results from idealized laboratory experiments and those from field data. Thus, at first, three bridge sites were selected and equipped with fathometers to find the bed elevation change in the vicinity of bridge pier over time. After and during the flooding, the stream flow variables and their bathymetry were measured using current viable technologies at the field. Then, to develop and suggest a laboratory modeling techniques, full three-dimensional physical models including measured river bathymetry and bridge geometry were designed and fabricated in a laboratory based on the scale ratio except for the sediment size, and the laboratory results were compared with the field measurements. Size of uniform sediment was carefully selected and used in the laboratory to explore the scale effect caused by sediment size scaling. The comparisons between laboratory results and field measurements show that the physical models successfully reproduced the flow characteristics and the scour depth around bridge foundations. With respect to the location of the maximum scour depth, they are not consistent with the results as in the previous research. Instead of occurring at the nose of each pier, the maximum scour depths are located further downstream of each pier column in several experimental runs because of the combination of complex pier bent geometry and river bathymetry, and the resulting unique flow motions around the pier bent
Photoprotection by 20-hydroxyvitamin D3, a product of CYP11A1 in skin
Skin cancer is one of the most common health issues afflicting people in many countries, particularly in Australia. The major cause of skin cancer is ultraviolet radiation (UV), which is also needed for vitamin D synthesis. There is also evidence from the Mason group that the hormonally active form of vitamin D, 1α,25-hydroxyvitamin D3 (1,25(OH)2D3), provides photoprotection. Studies on the effects of 20(OH)D3 on DNA damage and immunosuppression done in our laboratory by colleagues, revealed that 20(OH)D3 is as effective as 1,25(OH)2D3 in reducing thymine dimer formation and UVR-induced immunosuppression in female hairless Skh:hr1 mice (Tongkao-on et al., 2015). The aim of this project was to explore whether 20-hydroxyvitamin D3 (20(OH)D3), a product of vitamin D3 hydroxylation, provides protection against UV-induced photocarcinogenesis. In order to investigate whether the protection against acute UV-induced damage translates into prevention of skin carcinogenesis, the major, in vivo component of this study involved a 40 week photocarcinogenesis study and contact hypersensitivity (CHS) response experiment, with 1,25(OH)2D3 and 20(OH)D3 applied as topical treatments post UV irradiation. The results from the in vivo study showed that 1,25(OH)2D3 was effective at inhibiting UV-induced tumour formation and progression, but 20(OH)D3 was not observed to be effective in reducing the following parameters: tumour incidence, tumour latency, tumour multiplicity and squamous cell carcinoma (SCC) incidence
Putin and Trilateral Economic Cooperation between Moscow, Seoul, and Pyongyang: Motivation, Feasibility, and Korean Peace Process
Since 2000, President Vladimir Putin of Russia has persistently pushed for trilateral economic projects involving Moscow, Seoul, and Pyongyang, especially in the fields of energy (oil, gas, and electricity) and transportation (railroad). The Kremlin has long maintained that its proposed trilateral projects would not only be economically beneficial to all but also pave the road to inter-Korean reconciliation and peaceful unification. This article addresses three questions regarding Putin’s trilateral economic projects. What motivates Russia to push for the projects? Would they bring benefits to the three countries? Would they facilitate Korean peace process? The authors argue that Putin’s trilateral economic projects are part of Russia’s quest for power and search for a multipolar world order and should be understood from the theoretical framework of Bstructural realism.^ The research finds that the projects are not feasible due to North Korea’s nuclear crisis and economic uncertainties and may be implemented after the current North Korea’s nuclear crisis is resolved diplomatically, if North Korea’s leadership changes or if inter-Korean reconciliation and cooperation is achieved by the progressive government of Moon Jae-In
A Comprehensive Method of Calculating Maximum Bridge Scour Depth
Recently, the issues of scour around a bridge have become prominent because of the recurrent occurrence of extreme weather events. Thus, a bridge must be designed with the appropriate protection measures to prevent failure due to scour for the high flows to which it may be subjected during such extreme weather events. However, the current scour depth estimation by several recommended equations shows inaccurate results in high flow. One possible reason is that the current scour equations are based on experiments using free-surface flow even though extreme flood events can cause bridge overtopping flow in combination with submerged orifice flow. Another possible reason is that the current practice for the maximum scour depth ignores the interaction between different types of scour, local and contraction scour, when in fact these processes occur simultaneously. In this paper, laboratory experiments were carried out in a compound shape channel using a scaled down bridge model under different flow conditions (free, submerged orifice, and overtopping flow). Based on the findings from laboratory experiments coupled with widely used empirical scour estimation methods, a comprehensive way of predicting maximum scour depth is suggested which overcomes the problem regarding separate estimation of different scour depths and the interaction of different scour components. Furthermore, the effect of the existence of a pier bent (located close to the abutment) on the maximum scour depth was also investigated during the analysis. The results show that the location of maximum scour depth is independent of the presence of the pier bent but the amount of the maximum scour depth is relatively higher due to the discharge redistribution when the pier bent is absent rather than present
The Light and Period Variations of the Eclipsing Binary BX Draconis
New CCD photometric observations of BX Dra were obtained for 26 nights from
2009 April to 2010 June. The long-term photometric behaviors of the system are
presented from detailed studies of the period and light variations, based on
the historical data and our new observations. All available light curves
display total eclipses at secondary minima and inverse O'Connell effects with
Max I fainter than Max II, which are satisfactorily modeled by adding the
slightly time-varying hot spot on the primary star. A total of 87 times of
minimum light spanning over about 74 yrs, including our 22 timing measurements,
were used for ephemeris computations. Detailed analysis of the O-C diagram
showed that the orbital period has changed in combinations with an upward
parabola and a sinusoidal variation. The continuous period increase with a rate
of +5.65 \times 10^-7 d yr^-1 is consistent with that calculated from the
Wilson-Devinney synthesis code. It can be interpreted as a mass transfer from
the secondary to the primary star at a rate of 2.74 \times 10^-7 M\odot yr^-1,
which is one of the largest rates for contact systems. The most likely
explanation of the sinusoidal variation with a period of 30.2 yrs and a
semi-amplitude of 0.0062 d is a light-traveltime effect due to the existence of
a circumbinary object. We suggest that BX Dra is probably a triple system,
consisting of a primary star with a spectral type of F0, its secondary
component of spectral type F1-2, and an unseen circumbinary object with a
minimum mass of M3 = 0.23 M\odot.Comment: 24 pages, including 5 figures and 9 tables, accepted for publication
in PAS
Estimates of Discharge Coefficient in Levee Breach Under Two Different Approach Flow Types
The amount of released water (discharge) in a levee breach is a primary input variable to establish an emergency action plan for the area next to the levee. However, although several studies have been conducted, there is still no widely applicable discharge coefficient formula; this needs to be known to estimate discharge amount through an opening caused by a levee breach. Sometimes, the discharge coefficient developed for a sharp crested side weir is used to rate the discharge, but, in case of a levee breach, the resulting geometry and flow types are similar to that over a broad crested weir. Thus, in this study, two different openings—rectangular and trapezoidal shape—are constructed in the center of a levee at a height of 0.6m to replicate levee breach scenarios, and the effect of two different approach flow types—the river type approach and reservoir type approach—are explored to suggest a discharge coefficient formula applicable for discharge rating for a levee breach. The results show that the ratio of head above the bottom of an opening and the opening width is a key variable for calculating the discharge coefficient of a reservoir type, but the approach Froude number should also be considered for a river type approach. The measured data are used to improve rating equations and will be useful in the future to validate computational fluid dynamics simulations of wave propagation during levee failure into the inundation area
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