Sungjoo Hwang

The organ targetability of small and large albumin microspheres containing free and HSA conjugated methotrexate

Abstract The organ-targeting ability of [ 3 H]methotrexate ([ 3 H]MTX), [ 3 H]MTX-human serum albumin (HSA) conjugates, and small (mean volume diameter, 10.0 μm) and large (mean volume diameter, 22.4 μm) size hydrophilic albumin microspheres (HAMs) containing different ratios of [ 3 H]MTX-HSA conjugates to [ 3 H]MTX was evaluated after i.v. administration of the compounds, equivalent to 150 nCi via the tail vein of mice. The total radioactivity in the lung increased immediately in a few minutes after i.v. injection of the both small and large HAMs, and then declined for up to 3–4 weeks, apparently reaching a plateau thereafter. However, the radioactivity in the liver, spleen and kidney increased slowly during the rapid decrease in radioactivity in the lung. This suggested that the small and large HAMs administered could be entrapped rapidly in the lung through mechanical filtration because of their large size and slowly redistributed to the liver, spleen and kidney due to either the HAMs being degraded enough for the size to allow passage through the capillary beds of the lung and/or the release of [ 3 H]MTX or [ 3 H]MTX-HSA conjugates from the HAMs. The highest value of AUQ was obtained for the liver and lung from small (including [ 3 H]MTX-HSA conjugates) and large HAMs. respectively, and suggested that the small (including [ 3 H]MTX-HSA conjugates) and large HAMs have a better targeting ability to the liver and lung, respectively, than that of MTX or MTX-HSA conjugates. This is consistent with the higher value of r e ∗ for the liver and lung from the small and large HAMs, respectively. Greater selectivity for the liver and lung from the small and large HAMs, respectively, is indicated by a t e ∗ value greater than unity. The greater targeting efficiency of the small and large HAMs for the liver and lung is indicated by higher values of T c ∗ . However, the liver targeting efficiency of the small HAMs appeared to be similar to that of [ 3 H]MTX-HSA conjugates.

Boost, Control, or Both of Korean Housing Market: 831 Countermeasures

Although the Korean government reported a housing supply ratio of more than 100% in the early 2000s, regional and class disparities in the Korean housing sector have not been correspondingly alleviated. Unfortunately, many Korean households are still enduring the economic burden caused by cyclical price variation, while many housing construction companies are on the verge of bankruptcy. To resolve the ever-expanding socioeconomic problems in the housing and real estate sector, the current Korean government proposed 831 Countermeasures, which has since met with much controversy. In an effort to address these issues, this paper utilizes a qualitative system dynamics model to elucidate and interrogate complex Korean housing mechanisms. By mapping bibliographical and experimental knowledge with causal loop diagrams, the positive and adverse effects of the 831 Countermeasures are also analyzed. Finally, based on the research findings, alternative policy guidelines are proposed that can be used to strengthen positive housing structures and obviate negative ones.

Visualization, Information Modeling, and Simulation: Grand Challenges in the Construction Industry

AbstractWith the rapid advancement of sensing and computing technology and the wide adoption of mobile computing, the construction industry has faced a rise in the amount of information and data generated during the lifecycle of the construction project. To deal with a large variety of project data and information to support efficient and effective decision making, visualization, information modeling, and simulation (VIMS) has become critical in the development of capital facilities and infrastructures. The objective of this paper is to identify and investigate grand challenges in VIMS for the construction industry, to assist the academic and industry communities in establishing a future research agenda to solve VIMS challenges. In particular, 17 VIMS grand challenges were identified by an expert task force in the VIMS committee of the ASCE Computing and Information Technology Division, and then VIMS experts in the civil and construction areas from both academia and industry participated in a survey to as...

Information Retrieval Framework for Hazard Identification in Construction

AbstractThe repetitive occurrence of similar accidents in construction is one of the most prevalent characteristics of construction accidents. Similar accident cases provide direct information for determining the risks of scheduled activities and for planning safety countermeasures. Moreover, understanding these cases gives laborers the chance to evade and prepare for an expected accident in their workspaces. Researchers have developed many systems in order to retrieve and use past accident cases. Although the developed systems have a clear and limited target (user), most of them were developed under retrieval methods based on ad hoc systems, which can cause inconvenience to users in using the retrieval system. To overcome these limitations, this study proposes an automated information (about past accident case) retrieval system that can automatically search for and provide (as a push system) similar accident cases. The retrieval system extracts building information modeling (BIM) objects and composes a q...

Automated Time-Series Cost Forecasting System for Construction Materials

AbstractAs large-scale building projects increase in frequency, their construction costs become a matter of great concern, especially because of their lengthy construction periods. In particular, recent volatile fluctuations of construction material prices have fueled problems like cost forecasting. Many researchers try to accurately estimate cost escalations, but price forecasting for numerous construction materials requires a simplified and automated process. The research in this paper develops an automated time-series material cost forecasting (ATMF) system including both autoselected procedures for determining a best-fitting model and an autoextracting module for forecasting values using the Box-Jenkins approach. If the modeling process is simplified and iterative arbitrary decisions for the modeler eliminated, each future prices of a large number of materials can be forecast differently. Thus, the ATMF system can be utilized for predicting future trends in construction material costs. Further, an out...

Modeling the dynamics of urban development project: Focusing on self-sufficient city development

Abstract A self-sufficient city can be defined as a city where there is a defined perimeter, inside which lies a population that is self-sufficient: i.e., the economy within the city fully employs the population, and the services and cultural infrastructure within the city are sufficient supply for the population. This paper aims to analyze the dynamics of urban development projects, with a particular focus on the self-sufficient city development policy. To this end, key success factors relating to self-sufficient city developments are derived. A causal loop diagram is then constructed to analyze the interaction between elements of the self-sufficient city development and a system dynamics model is developed to perform quantitative analysis of urban development policies. The results indicate that all urban development policies are related to urban growth, but with varying types and degrees of influence. The ‘business inflow’ and ‘initial education welfare investment’ policies do influence quantitative urban population growth. However, the ‘initial houses’ and ‘initial service facility supply’ policies have arguably greater influence, as they assist in achieving stable urban population growth over time. Based on these results, it is concluded that the developed model has a potential to aid decision makers in assessing the impact of various self-sufficient urban development policies.

Hybrid Simulation Framework for Immediate Facility Restoration Planning after a Catastrophic Disaster

AbstractSince the effects of external conditions, such as limited resource supplies and poor working environments in damaged regions, are critical to facility restoration projects after a catastrophic disaster, a lack of understanding regarding restoration conditions may lead to unexpected delays and additional project costs. The fact that various elements of postdisaster restoration conditions interact with each other and vary with a facility’s surrounding damage and recovery situations over time makes many stakeholders’ comprehension even more challenging. To support immediate and appropriate facility restoration planning under changing project conditions, this study developed a hybrid system dynamics (SD)–discrete event simulation (DES) framework. In this hybrid restoration simulation, SD allows for a comprehensive understanding of the dynamic features of various restoration conditions, while DES enables an in-depth examination of facility restoration operations according to external condition changes....

EEG Signal-Processing Framework to Obtain High-Quality Brain Waves from an Off-the-Shelf Wearable EEG Device

AbstractInvestigating brain waves collected by an electroencephalogram (EEG) can be useful in understanding human psychosocial conditions such as stress, emotional exhaustion, burnout, and mental f...

A Study of the Tower Crane Hoisting Time Estimation Simulation Model with Climate Element for the High-Rise Building Construction

Tower crane hoisting plan is one of the key element for the success of entire High-Rise Building construction. Hoisting time is the basic factor to appropriate hoisting plan which need to the hoisting load estimate and tower crane selection. With this reason, accurate hoisting time is needed to the proper hoisting plan. The current hoisting time estimation for High-Rise Building focus on the hoisting cycle time estimation with historical data. However, this method underestimated the external influences like environmental factor. Thus, this paper aims to develop the hoisting time estimation model with discrete event simulation which include the wind influences with certain height. According to the simulation result, the hoisting time which applied wind influence is increasing with height growth. Because of the high speed wind, the upper area of building has more operation delay time than the mechanical operation time. Seoul, the research area, has the most fastest wind speed on April and the least on October. Due to these differences of wind speed, the hoisting time is estimated with significant differences between April and October. This hosting time estimation model would be used for estimating the influence of wind. Moreover, this could apply to make the realistic hoisting plan.

Dynamic Feasibility Analysis of the Housing Supply Strategies in a Recession: Korean Housing Market

AbstractEstablishing housing supply strategies in a stagnant housing market is a significant issue because of two contradictory and concurrent problems. The first is the long-cherished desire to supply low-cost housing for low- and middle-income families, and the second is the problem of high vacancy levels attributable to low-level sales rates. Governments have been continuously implementing various supply policies intended to distribute houses evenly and to keep supply and demand in balance. However, it is difficult to satisfy consumers, owners, and suppliers because of conflicting needs and requirements. This paper therefore applies a system dynamics methodology and offers an integrated model that encompasses the for-profit behavior of each market participant, analyzes supply policies, and suggests appropriate and effective policies. Utilizing the case of the Korean housing market, the proposed model simulates future trends in house prices, balances between supply and demand, construction companies’ ea...