• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.4
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• pp.41-53
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• 2014

There has been lots of discussions and new policies to encourage people to start new businesses. However, they key issue such as how to raise the success rate of new start-ups still needs to be resolved. Many believe that the success of policies and discussions for promoting entrepreneurship in Korea highly depends on how to lower the risks with which early stage start-ups encounter. In this backdrop, this study aims at providing an emerging approaches in entrepreneurship, 'lean start-up', which can work as an effective method with which early stage entrepreneurs can minimize challenges they face. Even though lean start-up is a widely accepted concept among practitioners and recognized as a useful tool for entrepreneurship and education, but has not got deserved attention from the academic world. This paper offers basic framework and key principles of lean start-ups, furthermore, shows Korean cases of step-by-step application methods of its concepts. It also suggest key issues in adopting lean start-up strategy. This study has implications and contributions for entrepreneurs, educators and researchers through providing comprehensive perspectives on process of the lean start-up strategy.

• Computational Structural Engineering
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• v.1 no.1
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• pp.113-122
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• 1988

A practical model for predicting the risk of fatigue failure of steel highway bridges is developed in this study. The proposed model is derived from fatigue reliability methods by incorporating various factors which may affect the fatigue life of bridges. The fatigue reliability function is assumed to follow the Weibull distribution. The computational form of the Weibull is adopted from Ang-Munse's approach that includes all the statistical uncertainties of the fatigue life of steel members and the stress ranges under variable amplitude loadings. The model accounts for the variation in ADTT, the change in stress history and the effects of inspections, which may occur during the serivce life of bridges. Stress range histograms are collected from the random stress spectra based on the field measurements of an existing bridge, and, thus, the resulting stress range frequency distribution is modelled with a beta distribution. The results of applications of the proposed fatigue analysis methods to an existing bridge show that the proposed models with the computer program developed for numerical computations can be used as a practical tool for the fatigue rating or for the predictions of the remaining fatigue life of deteriorated existing steel bridges.

• Journal of the Korean Society of Systems Engineering
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• v.14 no.1
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• pp.72-82
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• 2018

Generally speaking, because of complexity of engineering process, the systems engineering may be not easy to understand clearly and not easy to perform also. The status of systems engineering infrastructure of the some Korean industry is not matured yet, i.e., the systems engineering process, method, tool and environment is not implemented consistently within the steel making industry. These difficulties are more severe at the concept and basic design phase than the detail design phase relatively. Korean industry has lots of development project for the precedented systems and usually has matured domain knowledge for the precedented systems. Even though there is a mature domain knowledge of the precedented systems, the development project will lead to failure under the condition of engineering system is not well equipped. For the project success, it is very important to have a proper engineering execution system especially for the concept design and basic phase, which has a high abstraction and a large influence on the whole project. This paper proposes a minimized design process that can be easily applied to the concept and basic design phase of the precedented systems, instead of complex system engineering processes. This paper also proposes the application case of the minimized design process and methods for a Blast Furnace System.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.5
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• pp.605-613
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• 2007

The purpose of this study is to develop a structural analysis system of LNG pump tower structure. The system affords to build optimized finite element model and procedure of the pump tower structure. The pump tower structure is one of the most important components of LNG (liquefied natural gas) carriers. The pump tower structure is subject to sloshing load of LNG induced by ship motion depending on filling ratio. Three typer of loading components, which are thermal, inertia and self-gravity are considered in the analysis. The finite element analysis is performed with ANSYS commercial code. The failure of each members can be evaluated of API unity and punching shear in ABS rule. The GUI is newly developed using Tcl/tk script language. All these design and analysis procedures are embedded in to the analysis system successfully.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.4
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• pp.349-355
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• 2003

Material degradation due to corrosion fatigue was evaluated nondestructively using backward radiated Rayleigh surface wave. h corrosion fatigue test was carried out for the specimens made of thermo-mechanically controlled process steel in 3.5wt.% NaCl solution at $25^{\circ}C$. The backward radiation profile, which is the amplitude variation of backward radiated ultrasound according to the incident angle, of the specimens were measured in water at room temperature after the corrosion fatigue test. The velocity of Rayleigh surface wave, determined from the incident angle at which the profile of the backward radiated ultrasound became maximum, decreased for the specimen that had the large number of cycles to failure in the corrosion fatigue test. This fact implies that the corrosion degradation occurred at specimen surface in this specific test is dominantly dependant on the me exposed to corrosion environment. The result observed in the present work demonstrates the high potential of backward radiated Rayleigh surface wave as a tool for nondestructive evaluation of corrosion degradation of aged materials.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.71-77
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• 2014

Heavy rainfall induces many disasters including slope failure and infrastructure collapse. In this point of view, rainfall-simulated centrifugal model test can be a reasonable tool to evaluate the stability of geotechnical structure. In order to obtain the displacements of a model in centrifugal model test, in general, LVDT and laser displacement sensor are used. However, when the rainfall is simulated, the LVDT has the problem of excessive infiltration into the model ground, and the laser displacement sensor provides the measuring result with inaccuracy due to the dispersion of the laser radiation. Hence, in this study, horizontal displacement sensor for rainfall-simulated centrifugal model test was developed. This sensor produced with a thin elastic steel plate and gave the accurate relationship between the displacement and the strain.

• Korean Journal of Construction Engineering and Management
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• v.10 no.4
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• pp.67-75
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• 2009

The mixed-use development project like urban regeneration project has been enforced with long period and participation of various stakeholders. For this character, lots of risk could be occurred during the process of project and the project's success or failure depends on the risk management. So the process of identifying and responding to risks in urban regeneration projects should be followed systemically. The risk identification phase is the first step to identify risk factors and define risk's character. One of the risk identification methods, the checklist, is the most practical and well-known one. This study suggests the check list that devide risks classified by stakeholders through analizing tasks of stakeholders and drawing risks. This kind of checklist which handles risk factors classified by stakeholders is an easy tool to identify risks and expected to be effective to find risks for various stakeholders and themselves in the urban regeneration projects.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.4
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• pp.130-137
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• 1997

The demand for wire-cut EDM is increasing rapidly in the die and tool making industry. In this study machining characteristics such as machining rate, surface roughness, hand drum form and hardness of machined material are investigated experimentally under the conditions varing pulse on time, pulse off time, peak voltage, wire tension after fixing other conditions in SKD 11 and brass and brass workpiece. It was found that various operating conditions had significant influences on machining characteristics. But the hardness of workpiece was uneffected by operating conditions. Also it was obtained experimentally that brass workpeice had better machinability than SKD 11 one.dition according to the current(Ip) in an electric spark machine : 1) Electrode is utilized Cu and Graphite. 2) Work piece is used the material of carbon steel. The condition of experiment is : 1) Current is varied 0.7(A) to 50(A) and the time of electric discharging to work piece in each time is 30(min) to 60(min). 2) After the upper side of work piece was measured in radius(5$\mu$m) of stylus analyzed the surface roughness to ade the table and graph of Rmax by yielding data. 3) Electro wear ratio is : \circled1Cooper was measured ex-machining and post-machining by the electronic balance. \circled2The ex-machining of graphite measured by it, the post-machining was found the data from volume $\times$specific gravity and analyzed to made its table and graph on ground the data. 4) In order to keep the accuracy of voltage affected to the work piece was equipped with the A.V. R and the memory scope was sticked to the electric spark machine. 5) In order to preserve the precision of current, to get rid of the noise occured by internal resistance of electric spark machine and to force injecting for the discharge fluid , it made the fixed table for a work piece to minimize the work error by means of one's failure during the electric discharging.

• Childhood Kidney Diseases
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• v.19 no.2
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• pp.184-189
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• 2015

Poststreptococcal glomerulonephritis (PSGN) is one of the most well-known and important infectious renal diseases resulting from a prior infection with group A ${\beta}$-hemolytic streptococcus. The typical clinical characteristics of the disease reflect acute onset with gross hematuria, edema, hypertension and moderate proteinuria after the antecedent streptococcal infection. In children, usually PSGN is healed spontaneously but if it combines with fast progressing glomerulonephritis, it would be developed to chronic renal failure. Therefore, it is important to make a fast diagnosis and treatment by simple tools to predict the course and the prognosis of disease. Sonography is a simple tool for diagnosis but there is no typical renal sonographic finding in PSGN, so it is difficult to predict the course and the prognosis of disease by sonographic findings. In comparison between two cases of renal sonographic findings in PSGN, a patient who showed more increased echogenicity in more extended area of renal sonography had the severe results of renal pathology, prolonged treatment period and low serum C3 level. Here, we report the different findings of renal sonography and pathology depending on the degree of severity between two patients. Thus, it is necessary to gather more information from further studies to make a consensus about the relationship between the renal sonography and the prognosis of disease in PSGN.

• Journal of Pharmaceutical Investigation
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• v.40 no.spc
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• pp.1-7
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• 2010

Since the introduction of the biopharmaceutics classification system (BCS) in 1995, it has viewed as an effective tool to categorize drugs in terms of prediction for bioavailability (BA) and bioequivalence (BE). The BCS consist of four drug categories: class I (highly soluble and highly permeable), class II (low soluble and highly permeable), class III (highly soluble and low permeable) and class IV (low soluble and low permeable), and almost all drugs belong to one of these categories. Likewise, classifying drugs into four categories according to their solubility and permeability is simple and relatively not controversial, and thus the FDA adopted the BCS as a science-based approach in establishing a series of regulatory guidance for the industry. Actually, many pharmaceutical companies have gained a lot of benefits, which directly connect to cost loss and failure decrease in the early stage of drug development. Recently, instead of solubility, using dissolution characteristics (e.g. intrinsic dissolution rate) have provided an improvement in the classification in correlating more closely with in vivo drug dissolution rather than solubility by itself. Furthermore, a newly modified-version of BCS, biopharmaceutics drug disposition classification system (BDDCS), which classify drugs into four categories according to solubility and metabolism, has been introduced and gained much attention as a new insight in respect with the drug classification. This report gives a brief overview of the BCS and its implication, and also introduces the recent new trend of drug classification.