• Journal of Internet Computing and Services
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• v.5 no.2
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• pp.17-31
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• 2004

This paper presents a new assumptions statement generation method for developing TOE security environment section of PP. We surveyed on guides on the assumption statement in CC scheme, and collected and analyzed hundred of assumption statements which are in 26 certified and published real PPs and CC Toolbox/PKB. The CC Toolbox/PKB is included a class of pre-defined assumption statements. From the result of the survey, we developed a new generic assumption statement list, and proposed a assumption derivation method by using the list.

• Journal of the Korea Society of Computer and Information
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• v.23 no.2
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• pp.53-61
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• 2018

In this paper, the author proposes an efficient group key agreement scheme in a mobile environment where group members frequently join and leave. This protocol consists of basic protocols and general ones and is expected to be suitable for communications between a mobile device with limited computing capability and a key distributing center (or base station) with sufficient computing capability. Compared with other schemes, the performance of the proposed protocol is a bit more efficient in the aspects of the overall cost for both communication and computation where the computational efficiency of the scheme is achieved by using exclusive or operations and a one-way hash function. Also, in the aspect of security, it guarantees both forward and backward secrecy based on the computational Diffie-Hellman (CDH) assumption so that secure group communication can be made possible. Furthermore, the author proves its security against a passive adversary in the random oracle model.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.05a
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• pp.276-277
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• 2004

• Particle and aerosol research
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• v.14 no.1
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• pp.1-8
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• 2018

The optical force on a perfectly reflecting sphere in a ray-optics regime is considered. With the assumption of geometric optics and a sphere smaller than the minimum waist of the illuminating beam, closed-form analytic expressions of the optical force are derived. Both axial and radial forces are expressed by a modified Bessel function of the first kind. The derived analytic expressions are compared to precise numerical computations of the exact optical force equations derived previously. In addition the error due to the small sphere assumption is estimated analytically.

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.231-242
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• 2004

The effect of toxicants on ecological systems is an important issue from mathematical and experimental points of view. Here we have studied dynamical model of a single-species population-toxicant system. Two cases are studied: constant exogeneous input of toxicant and rapidly fluctuating random exogeneous input of toxicant into the environment. The dynamical behaviour of the system is analyzed by using deterministic linearized technique, Lyapunov method and stochastic linearization on the assumption that exogeneous input of toxicant into the environment behaves like ‘Coloured noise’.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2744-2746
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• 2003

ISO/IEC 15408 requires the TOE(Target of Evaluation) Security Environment section of a Protection Profile(PP) or Security Target(ST) to contain a list of assumptions about the TOE security environment or the intended usage of the TOE. This paper presents a specific conditions should be assumed to exist in the smart card environment and the analysis of those conditions developer of smart card PP must consider.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.354-355
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• 2003

In this study, a risk-based cleanup approach using the leaching potential was suggested for the soil vapor extraction (SVE) process. A multi-component model was adopted with local equilibrium assumption (LEA), and Raoult's law was applied to estimate the leaching potential for BTEX. Finally, a risk analysis was conducted based on the leaching pontential calculated. To complete the feasibility of this approach, more investigations and discussions will be required in future.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.2
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• pp.191-204
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• 2003

A one dimensional time dependent acid rain model considering size distribution of aerosols and hydrometeors is developed to predict observed chemical and physical properties of precipitation. Temporal variations of anions and cations observed are predicted fairly well with acid rain model simulations. It is found that aerosol depletion rates are highly dependent on aerosol sizes under the assumption of Marshall - Palmer raindrop size distribution. Also, the aerosol depletion during the initial rain event largely influences on ion concentrations in rainwaters.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.280-282
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• 2002

In analysis of pumping test data, generally infinite domain has been assumed. However, in many cases, this assumption was not readily satisfied. Some boundaries conditions and natural heterogeneity of hydrogeologic properties would play critical roles on groundwater flow and contaminant transport. This study examined effects of some boundary conditions and heterogeneity on the groundwater flow and contaminant transport with basic numerical groundwater modeling, which provides implications for remediation of contaminated groundwater.

• The Journal of the Acoustical Society of Korea
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• v.34 no.6
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• pp.470-478
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• 2015

A heuristic method treating a layered ocean bottom in a ray modeling is to use the plane wave reflection coefficient for multiple-layered structure, named an one-layer assumption in this paper. We examine the validity of one-layer assumption in the case of two-layered ocean bottom, and obtain a simple inequality condition depending on the sound speed ratio, the ratio of layer thickness to source-receiver range, and the grazing angle of first reflected ray. From this inequality condition, it is shown that an one-layer assumption can be applicable to ray propagation problems at mid frequencies. Finally, numerical experiments are performed in the ocean environment similar to the East Sea in Korea. Incoherent transmission loss is calculated by the geometrical beam model with the plane wave reflection coefficient for multiple-layered ocean bottom and compared with the result of SNUPE 2.0, which is a parabolic equation package developed in Seoul National University.