scholarly journals Prediction of direct runoff hydrographs utilizing stochastic network models: a case study in South Korea

2014 ◽  
Vol 11 (10) ◽  
pp. 11247-11279
Author(s):  
Y. Seo ◽  
S.-Y. Park

Abstract. In this study, we combine stochastic network models that reproduce the actual width function and the width function based instantaneous unit hydrograph (WFIUH) that directly makes use of a width function and converts it into runoff hydrographs. We evaluated the stochastic network models in terms of reproducing the actual width function and also the robustness of the semi-distributed model (WFIUH) in application to a test watershed in South Korea. The stochastic network model has an advantage that it replicates width functions of actual river networks, whereas the WFIUH has an advantage that the parameter values are physically determined, which can be potentially advantageous in prediction of ungauged basins. This study demonstrates that the combination of the Gibbsian model and the WFIUH is able to reproduce runoff hydrographs not just for the case of uniform rainfall over the test catchment but also for moving storms. Therefore, results of this study indicate that the impact of spatial and temporal rainfall variation on runoff hydrographs can be evaluated by the suggested approach in ungauged basins even without detailed knowledge of river networks. Once the regional similarity in river network configuration is identified, the proposed approach can be potentially utilized to estimate the runoff hydrographs for ungauged basins.

Author(s):  
Misa Kayama ◽  
Wendy Haight ◽  
May-Lee Ku ◽  
Minhae Cho ◽  
Hee Yun Lee

Stigmatization is part of the everyday lives of children with disabilities, their families, and their friends. Negative social encounters, even with perfect strangers, can dampen joyful occasions, add stress to challenging situations, and lead to social isolation. This book describes a program of research spanning a decade that seeks to understand disabilities in their developmental and cultural contexts. The authors are especially interested in understanding adults’ socialization practices that promise to reduce stigmatization in the next generation. Guided by developmental cultural psychology, including the concept of “universalism without uniformity,” the authors focus on the understandings and responses to disability and associated stigmatization of elementary-school educators practicing in Japan, South Korea, Taiwan, and the U.S. Educators from all four cultural groups expressed strikingly similar concerns about the impact of stigmatization on the emerging cultural self, both of children with disabilities and their typically developing peers. Educators also described culturally nuanced socialization goals and practices pertaining to inclusive education. In Japan, for instance, educators emphasized the importance of peer group belonging and strategies to support the participation of children with disabilities. In the U.S., educators placed relatively more emphasis on individual development and discussed strategies for the equitable treatment of children with disabilities. Educators in South Korea and Taiwan emphasized the cultivation of compassion in typically developing children. The understanding gained through examination of how diverse individuals address common challenges using cultural resources available in their everyday lives provides important lessons for strengthening theory, policy, and programs.


2021 ◽  
Vol 13 (3) ◽  
pp. 1286
Author(s):  
Chunil Kim ◽  
Hyobi Choi ◽  
Yeol Choi

South Korea became an aging society in 2000 and will become a super-aged nation in 2026. The extended life expectancy and earlier retirement make workers’ preparation for retirement more difficult, and that hardship might lead to poorer living conditions after retirement. As annuity payments are, in general, not enough for retirees to maintain their previous standard of living after retirement, retired households would have to liquidate their financial and real assets to cover household expenditures. As housing takes the biggest share of households’ total assets in Korea, it seems to be natural for retirees to downsize their houses. However, there is no consensus in the housing literature on housing downsizing, and the debate is still ongoing. In order to understand whether or not housing downsizing by retirees occurs in Korea, this paper examines the impact of the timing of retirement on housing consumption using an econometric model of housing tenure choice and the consumption for housing. The results show that the early retirement group living in more populated region does not downsize the house, while the timing of retirement is negatively associated with housing consumption for the late retirement group living in the peripheral region.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
C Borghi ◽  
J.G Wang ◽  
A.V Rodionov ◽  
M Rosas ◽  
I.S Sohn ◽  
...  

Abstract Background It is well established that single pill combination (SPC) therapies have the potential to improve patient adherence versus multi-pill regimens, thereby improving blood pressure control and clinical outcomes in populations with hypertension. Purpose To develop a microsimulation model, capturing different treatment pathways, to project the impact on clinical outcomes of using single pill combination therapies for the management of hypertension in five countries (Italy, Russia, China, South Korea and Mexico). Methods The model was designed to project health outcomes between 2020 and 2030 for populations with hypertension managed according to four different treatment pathways: current treatment practices [CTP], single drug with dosage titration first then sequential addition of other agents [start low and go slow, SLGS], free choice combination with multiple pills [FCC] and combination therapy in the form of a single pill [SPC]. Model inputs were derived from Global Burden of Disease 2017 dataset, including demographics, health status/risk factors, transition probabilities and treatment attributes/healthcare utilization, and the model incorporated real-world challenges to healthcare delivery such as access to care, SBP measurement error, adherence and therapeutic inertia. Simulated outcomes of mortality, incidence of chronic kidney disease (CKD), stroke and ischemic heart disease (IHD), and disability-adjusted life years (DALYs) due to these conditions were estimated for population of 1,000,000 simulated patients for each treatment pathway and country. Results SPC therapy was projected to improve health outcomes over SLGS, FCC and CTP over 10 years in all five countries. SPC was forecast to reduce mortality by 5.4% (Italy), 4.9% (Russia), 4.5% (China), 2.3% (South Korea) and 3.6% (Mexico) versus CTP and showed greater projected reductions in mortality than SLGS and FCC. DALYs were projected to be reduced with SPC therapy by between 5.7% (Italy) and 2.2% (South Korea) compared with CTP and reductions in the incidence of clinical events were also projected with SPC therapy, with decreases in the range of 11.5% (Italy) to 4.9% (South Korea) versus CTP. Conclusions Ten-year projections of clinical outcomes associated with different anti-hypertensive treatment pathways in five countries indicated that both combination therapies (FCC and SPC) are likely to reduce the disease burden of hypertension compared with conventional management approaches, with SPC showing the greatest overall benefits due to improved adherence. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Sanofi, Gentilly, France


2021 ◽  
Vol 6 (2) ◽  
pp. e004292
Author(s):  
Jung Ho Kim ◽  
Jiyeon Suh ◽  
Woon Ji Lee ◽  
Heun Choi ◽  
Jong-Dae Kim ◽  
...  

BackgroundRapid diagnostic tests (RDTs) are widely used for diagnosing Plasmodium vivax malaria, especially in resource-limited countries. However, the impact of RDTs on P. vivax malaria incidence and national medical costs has not been evaluated. We assessed the impact of RDT implementation on P. vivax malaria incidence and overall medical expenditures in South Korea and performed a cost–benefit analysis from the payer’s perspective.MethodsWe developed a dynamic compartmental model for P. vivax malaria transmission in South Korea using delay differential equations. Long latency and seasonality were incorporated into the model, which was calibrated to civilian malaria incidences during 2014–2018. We then estimated averted malaria cases and total medical costs from two diagnostic scenarios: microscopy only and both microscopy and RDTs. Medical costs were extracted based on data from a hospital in an at-risk area for P. vivax malaria and were validated using Health Insurance Review and Assessment Service data. We conducted a cost–benefit analysis of RDTs using the incremental benefit:cost ratio (IBCR) considering only medical costs and performed a probabilistic sensitivity analysis to reflect the uncertainties of model parameters, costs and benefits.ResultsThe results showed that 55.3% of new P. vivax malaria cases were averted, and $696 214 in medical costs was saved over 10 years after RDT introduction. The estimated IBCR was 2.5, indicating that RDT implementation was beneficial, compared with microscopy alone. The IBCR was sensitive to the diagnosis time reduction, infectious period and short latency period, and provided beneficial results in a benefit over $10.6 or RDT cost under $39.7.ConclusionsThe model simulation suggested that RDTs could significantly reduce P. vivax malaria incidence and medical costs. Moreover, cost–benefit analysis demonstrated that the introduction of RDTs was beneficial over microscopy alone. These results support the need for widespread adoption of RDTs.


2021 ◽  
Vol 7 (2) ◽  
pp. 135
Author(s):  
Hun Park ◽  
Jun-Hwan Park ◽  
Sujin Lee ◽  
Hyuk Hahn

The role of R&D (research and development) intensity on the effect of knowledge services on the business performance of firms has been discussed by using PLS-SEM and PLS-MGA methods. Research groups were divided into two groups, innovative and non-innovative. Respondents were classified into innovative firms if their R&D intensity was over 3% and vice versa. PLS-SEM and PLS-MGA results were compared for two groups and valuable insights were extracted. For innovative firms, knowledge services seemed to be verified and processed by the decision makers and utilized to achieve their business performance. On the other hand, a large number of non-innovative firms seemed to have a stronger tendency to utilize knowledge services directly for their business without sufficient verification by the decision makers.


Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 964
Author(s):  
Komeyl Baghizadeh ◽  
Dominik Zimon ◽  
Luay Jum’a

In recent decades, the forest industry has been growingly expanded due to economic conditions, climate changes, environmental and energy policies, and intense demand changes. Thus, appropriate planning is required to improve this industry. To achieve economic, social and environmental goals, a supply chain network is designed based on a multi-period and multi-product Mixed-Integer Non-Linear Programming (MINLP) model in which the objective is to maximize the profit, minimize detrimental environmental effects, improve social effects, and minimize the number of lost demands. In addition, to improve forest industry planning, strategic and tactical decisions have been implemented throughout the supply chain for all facilities, suppliers and machinery. These decisions significantly help to improve processes and product flows and to meet customers’ needs. In addition, because of the presence of uncertainty in some parameters, the proposed model was formulated and optimized under uncertainty using the hybrid robust possibilistic programming (HRPP-II) approach. The -constraint technique was used to solve the multi-objective model, and the Lagrangian relaxation (LR) method was utilized to solve the model of more complex dimensions. A case study in Northern Iran was conducted to assess the efficiency of the suggested approach. Finally, a sensitivity analysis was performed to determine the impact of important parameters on objective functions. The results of this study show that increasing the working hours of machines instead of increasing their number, increasing the capacity of some facilities instead of establishing new facilities and expanding the transport fleet has a significant impact on achieving predetermined goals.


Author(s):  
Sungho Cho ◽  
NaRi Shin ◽  
Dae Hee Kwak ◽  
Amy Chan Hyung Kim ◽  
Won Seok Jang ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Yury A. Rossikhin ◽  
Marina V. Shitikova ◽  
Phan Thanh Trung

In the present paper, the problem on impact of a viscoelastic sphere against a viscoelastic plate is considered with due account for the extension of plate’s middle surface and local bearing of sphere and plate’s materials via the Hertz theory. The standard linear solid models with conventional derivatives and with fractional-order derivatives are used as viscoelastic models, respectively, outside and within the contact domain. As a result of impact, transient waves (surfaces of strong discontinuity) are generated in the plate, behind the wave fronts of which up to the boundaries of the contact domain the solution is constructed in terms of one-term ray expansions due to short-time duration of the impact process. The motion of the contact zone occurs under the action of extension forces acting in the plate’s middle surface, transverse force, and the Hertzian contact force. The suggested approach allows one to find the time-dependence of the impactor’s indentation into the target and the Hertzian contact force.


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