• Journal of the Korean Society of Groundwater Environment
• /
• v.7 no.1
• /
• pp.20-23
• /
• 2000

A general solution for determining the storage coefficient from multi-step pumping test recovery data is suggested. This solution is essentially based on the method of Banton and Bangoy (1996), which used single-step pumping test recovery data. The suggested solution can be applied to any-step pumping test recovery data. We have demonstrated the applicability of the general solution to single-, double-, and triple-step pumping and/or step-drawdown test data partially described in Lee and Lee (1999). The estimates of storage coefficient as well as transmissivity are well consistent with the values from other methods for pumping phase data.

• Journal of Korean Society of Transportation
• /
• v.13 no.3
• /
• pp.53-65
• /
• 1995

Proposed are model and its solution algorithm for determining the minimum number of high speed exits and their locations. While the previous researches on exit location aimed to minimize the average runway occuancy time (ROT) of an aircraft mix, the proposed approach is to find the minimum number of exits required to meet maximum allowable ROT. The rationale behind the approach is that the capacity of a runway increases as the ROT decreases down to some value, but not any more even though the ROT keep decreasing below the value. Hence, a maximum allowable ROT might be set up without declining the capacity. The problem is transformed into a shortest path problem on a specially constructed network and Dijkstra's labeling algorithms is employed to solve the problem A hypothetical example is provided to illustrate how the algorithms solves the problem.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.234-241
• /
• 1996

Trip-based material handling systems such as AGV systems, lift trucks, etc. are often designed with a given flow matrix (or FROM-TO chart) which is usually treated as the number of loaded trips that the devices must perform per unit time between the stations. In reality, the number of trips that would result from parts flow in a facility is dictated by the transfer batch size, i.e., the number of parts that are transferred from one station to the next in one trip. In this paper, we present analytical and simulation results aimed at determining optimal or near-optimal transfer batch sizes in manufacturing systems.

• Journal of the Korean Regional Science Association
• /
• v.15 no.3
• /
• pp.33-51
• /
• 1999

After the 1997 currency crisis, the real estate prices had been rapidly dropped and the deregulation in the Korean real estate merket has been performed. It is analyzed whether these transactions caused a structural change in real estate market, or not. The Pettitt test shows there exists a turing point in real estate prices in 1998. It is found that the degrees of co-movement between the change in real estate prices and real GDP growth rate are increased. Consequently, the factor, represented as real GDP growth rate, determining the market fundamental of real estate prices will effect on the behavioral pattern and the real estate prices in the long run. While the factors determining the portfolio selection behaviors, such as interest rate and stock prices, will cause short-term variations.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.9
• /
• pp.1741-1747
• /
• 2011

Though various techniques have been studied as a way of adjusting parameters of PID controllers, no perfect method of determining parameters is available to date. This paper proposes a new method for enhancing performance of PID controllers by using the characteristics of dual-input describing function (DIDF). In other words, if nonlinear elements with two inputs (DIDF) are connected in series to the plant, the critical point (-1+j0) for Nyquist stability theory can be moved to a position arbitrarily selected on the complex plane by determining necessary coefficients of the DIDF appropriately. This makes the application of the existing conventional PID parameter tuning methods a lot easier, and stability and robustness of the system are improved simultaneously due to the DIDF inserted.

• Korean Institute of Interior Design Journal
• /
• no.13
• /
• pp.197-202
• /
• 1997

In this study, we surveyed historical housing settlements of Hwangjon in Bonghwa-a clan village in Youngnam district which was formed in the Chosun Dynasty. We observe the relationships among the spatial layout of clan villages, the water flows and the family hierarchies as follows; (1) when a clan village was initially formed, the water flow, which is the phylosophical foundation of Poong Soo, was the most important factor for determining the original location; (2) as villages prosper, the water flow and the family hierarchy still played an important role in determining the following geological locations; (3) in modern age, however, the water flow and the family hierarchy lost the role in detrmining the geological locations; (4) consequently, in present days, each household becomes isolated from the village. Reflecting on these observations, for village to be maintained, we conclude that we need novel practical and cohesive village forming drives that can replace the water flows and the family hierarchy in the past.

• Journal of the Korean Society of Safety
• /
• v.29 no.5
• /
• pp.82-87
• /
• 2014

The procedures of safety diagnosis assessment have been applied by synthetical consideration of structural safety, functionality, and economic efficiency in determining reconstruction or remodeling, but they have limitations in some special cases such as the non-association apartment. In this regard, this study was conducted to establish more desirable criteria and procedures in determining reconstruction or new construction and suggests a way to improve policy and laws of reconstruction correctly by reviewing the safety diagnosis in reconstruction process. Besides, the safety diagnosis of reconstruction for non-association apartments in government-owned public district was carried out preemptively to remove reckless procedures. As a result, the reconstruction of non-association apartments should be effectively without interference in the administrative procedures. This requires that the policy and laws of reconstruction safety diagnosis should be revised in priority in order that similar projects in future can be effectively executed.

• Structural Engineering and Mechanics
• /
• v.28 no.2
• /
• pp.189-206
• /
• 2008

In several design codes and specifications, simplified formulae and charts are given for determining the effective lengths of frame columns. It is shown that these formulae may yield rather erroneous results in certain cases. This is due to the fact that, the code formulae utilise only local stiffness distributions. In this paper, a simplified procedure for determining approximate values for the buckling loads of braced frames is developed. The procedure utilises a fictitious load analysis of frames and yields errors less than 10%, which may be considered suitable for design purposes. The proposed procedure is applied to several numerical examples and it is shown that all the errors are in the acceptable range.

• Structural Engineering and Mechanics
• /
• v.19 no.1
• /
• pp.55-71
• /
• 2005

In several design codes and specifications, simplified formulae and diagrams are given for determining the buckling lengths of frame columns. It is shown that these formulae may yield rather erroneous results in certain cases. This is due to the fact that, the code formulae utilise only local stiffness distributions. In this paper, a simplified procedure for determining approximate values for the buckling loads of multi-storey frames is developed. The procedure utilises lateral load analysis of frames and yields errors in the order of 10%, which may be considered suitable for design purposes. The proposed procedure is applied to several numerical examples and it is shown that all the errors are in the acceptable range and on the safe side.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.11a
• /
• pp.134-137
• /
• 2006

Satisfying the customer orders with a short lead-time is one of the essential and competitive factors for business units under a mass customization environment. To shorten the lead-time for fulfilling various orders entails the production capacity expansion and efficient operational policy. Most business firms utilize the multiple production lines or facilities to cope with this business and manufacturing environment by making the manufacturing and distribution more flexible. In this study, we introduce the operational problem determining the joint production and delivery policy in an environment where multiple products are manufactured with more than one production lines. Also, we propose the heuristic solution approach for determining the product-line selection and joint lot size for this problem.