• Proceedings of the Korea Water Resources Association Conference
• /
• 2018.05a
• /
• pp.176-176
• /
• 2018

This study presents a regional, probabilistic framework for estimating streamflow via spatial scaling in the Great Lakes basin, which is the largest lake system in the world. The framework follows a two-fold strategy including (1) a quadratic-programming based optimization model a priori to explore the model structure, and (2) a time-varying hierarchical Bayesian model based on insights found in the optimization model. The proposed model is developed to explore three innovations in hierarchical modeling for reconstructing historical streamflow at ungaged sites: (1) information of physical characteristics is utilized in spatial scaling, (2) a time-varying approach is introduced based on climate information, and (3) heteroscedasticity in residual errors is considered to improve streamflow predictive distributions. The proposed model is developed and calibrated in a hierarchical Bayesian framework to pool regional information across sites and enhance regionalization skill. The model is validated in a cross-validation framework along with four simpler nested formulations and the optimization model to confirm specific hypotheses embedded in the full model structure. The nested models assume a similar hierarchical Bayesian structure to our proposed model with their own set of simplifications and omissions. Results suggest that each of three innovations improve historical out-of-sample streamflow reconstructions although these improvements vary corrsponding to each innovation. Finally, we conclude with a discussion of possible model improvements considered by additional model structure and covariates.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.7 no.1
• /
• pp.4-14
• /
• 2005

CarboKorea and HydroKorea are the domestic projects aiming to improve our understanding of carbon and water cycles in a typical Korean forest located in a complex terrain with a watershed connected to large rivers. The ultimate goal is to provide a nowcasting of these cycles for the whole Peninsula. The basic strategy to achieve such goal is through the inter- and multi-disciplinary studies that synthesize the in-situ field observation, modeling and remote sensing technology. The challenge is the fact that natural ecosystems are nonlinear and heterogeneous with a wide range of spatio-temporal scales causing the variations of mass and energy exchanges from a leaf to landscape scales. Our paradigm now shifts from temporal variation at a point to spatial patterns and from spatial homogeneity to complexity of water and carbon at multiple scales. Yet, a large portion of our knowledge about land-atmosphere interactions has been established based on tower observations, indicating that the development of scaling logics holds the key to the success of CarboKorea and HydroKorea. Here, we review the pioneering work of FIFE (First ISLSCP Field Experiment) on scaling issues in a temperate grassland and discuss the lessons from it for the application to Gwangneung forest site.

• Journal of Korean Society for Geospatial Information Science
• /
• v.19 no.2
• /
• pp.19-27
• /
• 2011

The objective of this study was to suggest technical approaches for preparation and down scaling of climate data used for predicting the potential forest distribution. To predict the forest distribution, we employed a Korean-specific forest distribution model, so-called the TAG(Thermal Analogy Group), and defined the PFT(Plant Functional Types) based on the HyTAG(Hydrological and Thermal Analogy Group). The climate data with 20km spatial resolution were interpolated to fit on the input data format with 1km spatial resolution. Two potential forest distribution maps were estimated using climate data constructed by kriging, one of the interpolation and down-scaling approaches, with and without lapse rate considered. Through the verification process by comparing two potential maps with the actual vegetation map, the forest distribution using the lapse rate was proven to be 38% more accurate.

• Journal of Biomedical Engineering Research
• /
• v.31 no.2
• /
• pp.134-140
• /
• 2010

Readily available high resolution brain MRI scans allow detailed visualization of the brain structures. Researchers have focused on developing methods to quantify shape differences specific to diseased scans. We have developed a novel method to quantify shape information for a specific population based on Multidimensional scaling(MDS). MDS is a well known tool in statistics and here we apply this classical tool to quantify shape change. Distance measures are required in MDS which are computed from pair-wise image registrations of the training set. Registration step establishes spatial correspondence among scans so that they can be compared in the same spatial framework. One benefit of our method is that it is quite robust to errors in registrations. Applying our method to 13 brain MRI showed clear separation between normal and diseased (Cushing's syndrome). Intentionally perturbing the image registration results did not significantly affect the separability of two clusters. We have developed a novel method to quantify shape based on MDS, which is robust to image mis-registration.

• Journal of the Korean housing association
• /
• v.1 no.2
• /
• pp.1-11
• /
• 1990

A study of domestic furniture arrangements may reveal the living style relevant to the room as conceived and coded by occupants and the effects of the physical environment on the structure of behavior settings. The purpose of this study was to investigate, through analizing the furniture usage and behavior as a non-reactive and activity oriented behavioral measures, the occupants` domestic habits as a living style using MDS. MDS(multidimensional scaling technique) is a statistical technique for creating a spatial representation of data. It Is a particularly appropriate technique for analizing qualitative data such as the furniture usage and behavior because it takes into account all of the relationships between items. For the MDS analysis, the furniture usage and behavior examined by housing types based on 114 households in Seoul. The result of spatial configuration by MDS has three dimensions : recogn;lion of room function, pattern of room organization, understanding of room meaning. The effect of housing types for dimensions is identical but configuration of furniture items is different.

• Journal of the Korean Geographical Society
• /
• v.42 no.5
• /
• pp.691-709
• /
• 2007

This paper investigates the social and political construction of geographical scale in conjunction with Korean housing politics. Recently, attention has been drawn to the issue of the social and political construction of geographical scale. Spatial scales have increasingly been regarded as socially constructed and politically contested rather than ontologically pregiven or fixed. The scale literature has paid attention to how different spatial scales can be used or articulated in social movements, with an emphasis on 'up-scaling' and 'scales of activism' rather than 'down-scaling' and 'scales of regulation.' Furthermore, the scale literature has focused on the aspect of empowerment. However, it is worthwhile to examine how scale-especially 'down-scaling' and 'scales of regulation'-can be used not only for marginalizing or excluding unprivileged social groups, but also for controlling the (re)production of space, including housing space. Under a regulatory regime, the Korean central government gained more control over the (re)production of housing space at geographical multi-scales by means of 'jumping scales,' specifically 'down-scaling.' The Korean central government has increasingly obtained the capacity to 'jump scales' by using not only multiscalar strategies for housing developments, but also taking advantage of various scales of institutional networking among the central and local governments, quasi-governmental institutions, and Chaebols, across the state. Traditionally, scale has been regarded as an analytical spatial unit or category. However, scale can be seen as means of inclusion(and exclusion) and legitimation. Choosing institutions to include or exclude cannot be separated from the choices and range of spatial scale, and is closely connected to 'scale spatiality of politics.' Facilitating different forms of 'scales of regulation,' the Korean central government included Chaebols and upper- and middle-income groups for the legitimization of housing projects, but excluded local-scale grassroots organizations and unprivileged social groups as decision-makers.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.259-264
• /
• 2006

It is well known that the uncertainty of the covariance parameters of the process noise (Q) and the observation errors (R) has a significant impact on Kalman filtering performance. Q and R influence the weight that the filter applies between the existing process information and the latest measurements. Errors in any of them may result in the filter being suboptimal or even cause it to diverge. The conventional way of determining Q and R requires good a priori knowledge of the process noises and measurement errors, which normally comes from intensive empirical analysis. Many adaptive methods have been developed to overcome the conventional Kalman filter's limitations. Starting from covariance matching principles, an innovative adaptive process noise scaling algorithm has been proposed in this paper. Without artificial or empirical parameters to be set, the proposed adaptive mechanism drives the filter autonomously to the optimal mode. The proposed algorithm has been tested using road test data, showing significant improvements to filtering performance.

• Journal of Korean Society of Rural Planning
• /
• v.4 no.1
• /
• pp.15-21
• /
• 1998

The purpose of the study is to identify a basic spatial unit for rural village redevelopment plan. An ideal spatial unit need to satisfy three basic premises: to be homogeneous as rural community, to be appropriate to implement the project, and to be compatible with regional planning systems. A spatial unit could, empirically, be defined based on the homogeneity at first, and then appropriateness and compatibility could be used to adjust its boundary. Mitan-Myun(13 villages), Pyungchang County, Dochuck-Myun(15 villages), Kwangju County, and Chuksan-Myun(28 villages), Kimje City in Korea were selected as case study areas. The degree of interrelationship between all possible pairs in each Myun was measured using spatial, socio-cultural, and economic indicators. Multidimensional Scaling(MDS) was used to identify a homogeneous spatial unit, and then indicators representing appropriateness and compatibility were used to adjust the identified boundary. New districts which have two or three villages were suggested as a reasonable spatial unit for rural village redevelopment, and its boundary roughly overlaps with Bup-Jeong-Ri(法定里: a legally defined village).

• Korean Institute of Interior Design Journal
• /
• v.16 no.6
• /
• pp.65-76
• /
• 2007

This research is progressed on the premise that there is a basic rule to organize a space in form generation process. In this study first, antecedent researches are inquired, and formal vocabularies related with form generation in space design are founded. Generally in the organizing process of spatial form designer could have selectively combined formal vocabularies consciously or unconsciously, and these formal vocabularies related with form generation are classified with 'formal elements' and 'spatial relationships'. First, as formal elements '2-dimensional line elements(rectilinear, oblique-linear, curvilinear)' are chosen. Second, formal vocabularies of 'spatial relationships' are 37 extracted from literatures related with architectural language or spatial language. Among them there are several vocabularies with similar or same meaning, they are unitized to representative one. Thereupon 20 vocabularies are finally selected as the formal vocabularies of 'spatial relationships', they are addition, subtraction, intersection, superimposition, juxtaposition, shifting, rotation, reflection, scaling, stretching, shear, bending, folding, distortion, articulation, deconstruction, symmetry, repetition, proportion, and asymmetry.

• Earthquakes and Structures
• /
• v.6 no.4
• /
• pp.375-392
• /
• 2014

Time history analyses have been preferred commonly in earthquake engineering area to determine earthquake performances of structures in recent years. Advances in computer technology and structural analysis have led to common usage of time history analyses. Eurocode 8 allows the use of real earthquake records as an input for linear and nonlinear time history analyses of structures. However, real earthquake records with the desired characteristics sometimes may not be found, for example depending on soil classes, in this case artificial and synthetic earthquake records can be used for seismic analyses rather than real records. Selected earthquake records should be scaled to a code design spectrum to reduce record to record variability in structural responses of considered structures. So, scaling of earthquake records is one of the most important procedures of time history analyses. In this paper, four real earthquake records are scaled to Eurocode 8 design spectrums by using SESCAP (Selection and Scaling Program) based on time domain scaling method and developed by using MATLAB, GUI software, and then scaled and real earthquake records are used for linear time history analyses of a six-storied building. This building is modeled as spatial by SAP2000 software. The objectives of this study are to put basic procedures and criteria of selecting and scaling earthquake records in a nutshell, and to compare the effects of scaled earthquake records on structural response with the effects of real earthquake records on structural response in terms of record to record variability of structural response. Seismic analysis results of building show that record to record variability of structural response caused by scaled earthquake records are fewer than ones caused by real earthquake records.