• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.3
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• pp.93-114
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• 2002

This paper suggests a dynamic balanced scorecard (DBSC) model employing the concept of system dynamics (SD), which could overcome the limitations inherent in the conventional balanced scorecard (BSC) and facilitate strategic learning process in organizations. The BSC has been a successful framework for measuring an organization＇s performance in various Perspectives through translating an organization＇s vision and strategy into an interrelated set of key performance indicators and specific actions. The BSC, while having significant strengths over traditional performance measurement methods, however, has its own limitations, due to its static nature, such as overlooking two-way causation between performance Indicators and neglecting the impact of delayed feedback flowing from the adoption of new strategies or policy changes. To overcome these limitations, we employs SD, a methodology for understanding complex systems where dynamic feedback among the interrelated system components significantly impact on the system outcomes. The SD simulation model in the form of DBSC we suggest in this paper would serve as a useful strategic learning tool for facilitating an organization＇s communication process through various scenario analyses as well as predicting the dynamic behavior pattern of their key performance measures over a future time frame. For the demonstration purpose, we apply the DBSC model to Korea Coal Corporation (KoCoal ) BSC case.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.2
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• pp.69-80
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• 2013

This study evaluates the seismic performance of road tunnels designed before the provisions for seismic design of tunnels were first established in 1999. Extensive design data and site investigation reports are investigated to select tunnels sections that are considered to be most susceptible to seismically induced damage under earthquake loading. Detailed analyses are performed on selected tunnels. The methods used are method of displacement and dynamic analysis. In performing the method of displacement, which is a type of pseudo-static analysis method used for underground structures, full domain and reduced domain modeling were used. The dynamic analyses are performed using finite difference method and using nonlinear constitutive model. Comparisons show that the reduced domain method of displacement match very closely with the dynamic analysis, demonstrating that it is the most suitable method for evaluating the seismic performance of road tunnels built in rocks. It is also shown that road tunnels, for which seismic design were not applied, are safe under the seismic risks corresponding to an earthquake with a return period 1000 years. It is concluded that additional seismic retrofit of tunnels is not necessary.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.2
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• pp.87-94
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• 1999

The Morison's formula has been commonly used in the determination of wave forces of sinusoidal waves acting on coastal or ocean structures of pile-supported type. In the case that plunging breakers are incident, the structures are subjected to impulsive breaking wave forces which are normally much larger than the Morison's. However, the impulsive breaking wave forces act in a very short time, and hence a dynamic structural analysis should be done to determine whether or not to include the forces in the design force items. In the present study, numerical methods for calculating the dynamic response of a vertically located cylindrical pile are developed. Static and dynamic displacements are then compared through several example analyses varying the structural properties of pile.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.55-60
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• 2004

In this study, the configuration and tension of a towing cable for side-scan sonar are predicted in an ambient flow and at an unsteady towing condition. The governing equation of three-dimensional dynamic analysis for a flexible cable is solved using a finite difference method. We successfully predict the configuration and tension of a side-scan sonar and designed the towing system. It is found in static analyses that the side-scan sonar must be towed to keep a its stable depth at a reasonable speed. The study also reveals in the transient analyses that the dominant component affecting the top tension is the tangential drag force for the larger towing speed than the critical speed, and the self weight of a towed instrument for the smaller towing speed than. It should be maneuvered for a towing vessel with good consideration for the impact effect in a cable due to tension peak when a towing speed is suddenly increase. The developed program can be applicable for three-dimensional dynamic analysis of a towing system for various marine survey instruments.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.5 s.45
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• pp.11-19
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• 2005

Seismic design of a building is usually performed by using the linear static procedure. However, the actual behavior of the building subjected to earthquake is inelastic and dynamic in nature. Therefore, inelastic dynamic analysis is required to evaluate the safety of the structure designed by the current design codes. For the validation, a RC special moment resisting frame building was chosen and designed by IBC 2003 representing new codes. Maximum plastic rotation and dissipated energy of some selected members were calculated for examining if the inelastic behavior of the building follows the intention of the code, and drift demand were calculated as well for checking if the building well satisfies the design drift limit. In addition, the effect of including internal moment resisting frames (non lateral resisting system) on analyses results was investigated. As a result of this study, the building designed by IBC 2003 showed the inelastic behavior intended in the code and satisfied the design drift limit. Furthermore, the internal moment resisting frames should be included in the analytical model as they affect the results of seismic analyses significantly.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.203-209
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• 2003

In this study, the configuration and tension of a towing cable for side-scan sonar are predicted in an ambient flow and at an unsteady towing condition. The governing equation of three-dimensional dynamic analysis for a flexible cable is solved using a finite difference method. We successfully predict the configuration and tension of a side-scan sonar and designed the towing system. It is found in static analyses that the side-scan sonar must be towed to keep a its stable depth at a reasonable speed. The study also reveals in the transient analyses that the dominant component affecting the top tension is the tangential drag force for the larger towing speed than the critical speed, and the soft weight of a towed instrument for the smaller towing speed than. It should be maneuvered for a towing vessel with good consideration for the impact effect in a cable due to tension peak when a towing speed is suddenly increase. The developed program can be applicable for three-dimensional dynamic analysis of a towing system for various marine survey instruments.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.5
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• pp.185-190
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• 2006

The security analysis relates to the ability of the electric systems to survive sudden disturbances such as electric short circuits or unanticipated loss of system elements. It is composed of both steady state and dynamic security analyses, which are not two separate issues but should be considered together. In steady state security analysis including voltage security analysis, the analysis checks that the system is operated within security limits by OPF (optimal power flow) after the transition of a new operating point. On the other hand, dynamic security analysis deals that the transition will lead to an acceptable operating condition. Transient stability, which is the ability of power systems to maintain synchronism when subjected to a large disturbance, is a principal component in dynamic security analysis. Usually any loss of synchronism will cause additional outages. They make the present steady state analysis of the post-contingency condition inadequate for unstable cases. This is the reason of the need for dynamics of systems. Probabilistic criterion can be used to recognize the probabilistic nature of system components and shows the possibility of system security. A comprehensive conceptual framework for probabilistic static and dynamic assessment is presented in this paper. The simulation results of the Western System Coordinating Council (WSCC) system compare an analytical method with Monte-Carlo simulation (MCS). Also, a case study of the extended IEEE Reliability Test System (RTS) shows the efficiency of this approach.

• Advances in concrete construction
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• v.9 no.5
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• pp.503-510
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• 2020

Concrete dams are important structures due to retaining amount of water on their reservoir. So such kind of structures have to be designed against static and dynamic loads. Especially considering on critical importance against blasting threats and environmental safety, dams have to be examined according to the blast loads. This paper aims to investigate structural response of concrete gravity dams under blast loads. For the purpose Sarıyar Concrete Gravity Dam in Turkey is selected for numerical application with its 85 m of reservoir height (H), 255 m of reservoir length (3H), 72 m of bottom and 7 m of top widths. In the study, firstly 3D finite element model of the dam is constituted using ANSYS Workbench software considering dam-reservoir-foundation interaction and a hydrostatic analysis is performed without blast loads. Then, nearly 13 tons TNT explosive are considered 20 m away from downstream of the dam and this is modeled using ANSYS AUTODYN software. After that explicit analyses are performed through 40 milliseconds. Lastly peak pressures obtained from analyses are compared to empirical equations in the literature and UFC 3-340-02 standard which provide unified facilities criteria for structures to resist the effects of accidental explosions. Also analyses' results such as displacements, stresses and strains obtained from both hydrostatic and blasting analysis models are compared to each other. It is highlighted from the study that blasting analysis model has more effective than the only hydrostatic analysis model. So it is highlighted from the study that the design of dams should be included the blast loads.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.1
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• pp.9-22
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• 2022

A fighter performing a reconnaissance mission is equipped with a pod that drives optical/infrared sensors for acquiring and identifying target information on the lower part of the fuselage. Due to the nature of the reconnaissance mission, the fighter performs high speed evasive maneuvers, and the resulting load should be considered importantly for the development of the pod. This paper concerns a numerical investigation into the inertial and aerodynamic loads of the airborne pod of high performance aircrafts. For the aerodynamic load analysis, the pylon and pod shapes are added to the fighter 3D model, and the commercial software was used for static and dynamic analysis. Considering the practical mission conditions, the common/extreme conditions were established respectively in the static and dynamic situations of pods and the driving torque could be tripled under dynamic conditions. In the analysis of inertia load, a 3-DOF model considering roll and turning maneuvers was derived by the Lagrangian method, and then the numerical integration method was applied to the analysis. As a results, it was conformed that the inertia load was generally induced at a low level compared to the aerodynamic load, but depending on the unbalance mass condition of the pod, the inertia load cannot be negligible.

• Asia Marketing Journal
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• v.16 no.1
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• pp.35-69
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• 2014

The impact of competition on pricing has been studied in the context of counterfactual merger analyses where expected optimal prices in a hypothetical monopoly are compared with observed prices in an oligopolistic market. Such analyses would typically assume static decision making by consumers and firms and thus have been applied mostly to data obtained from consumer packed goods such as cereal and soft drinks. However such static modeling approach is not suitable when decision makers are forward looking. When it comes to the markets for durable products with indirect network effects, consumer purchase decisions and firm pricing decisions are inherently dynamic as they take into account future states when making purchase and pricing decisions. Researchers need to take into account the dynamic aspects of decision making both in the consumer side and in the supplier side for such markets. Firms in a two-sided market typically subsidize one side of the market to exploit the indirect network effect. Such pricing behaviors would be more prevalent in competitive markets where firms would try to win over the battle for standard. While such qualitative expectation on the relationship between pricing behaviors and competitive structures could be easily formed, little empirical studies have measured the extent to which the distinct pricing structure in two-sided markets depends on the competitive structure of the market. This paper develops an empirical model to measure the impact of competition on optimal pricing of durable products under indirect network effects. In order to measure the impact of exogenously determined competition among firms on pricing, we compare the equilibrium prices in the observed oligopoly market to those in a hypothetical monopoly market. In computing the equilibrium prices, we account for the forward looking behaviors of consumers and supplier. We first estimate a demand function that accounts for consumers' forward-looking behaviors and indirect network effects. And then, for the supply side, the pricing equation is obtained as an outcome of the Markov Perfect Nash Equilibrium in pricing. In doing so, we utilize numerical dynamic programming techniques. We apply our model to a data set obtained from the U.S. video game console market. The video game console market is considered a prototypical case of two-sided markets in which the platform typically subsidizes one side of market to expand the installed base anticipating larger revenues in the other side of market resulting from the expanded installed base. The data consist of monthly observations of price, hardware unit sales and the number of compatible software titles for Sony PlayStation and Nintendo 64 from September 1996 to August 2002. Sony PlayStation was released to the market a year before Nintendo 64 was launched. We compute the expected equilibrium price path for Nintendo 64 and Playstation for both oligopoly and for monopoly. Our analysis reveals that the price level differs significantly between two competition structures. The merged monopoly is expected to set prices higher by 14.8% for Sony PlayStation and 21.8% for Nintendo 64 on average than the independent firms in an oligopoly would do. And such removal of competition would result in a reduction in consumer value by 43.1%. Higher prices are expected for the hypothetical monopoly because the merged firm does not need to engage in the battle for industry standard. This result is attributed to the distinct property of a two-sided market that competing firms tend to set low prices particularly at the initial period to attract consumers at the introductory stage and to reinforce their own networks and eventually finally to dominate the market.