• The KIPS Transactions:PartC
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• v.11C no.1
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• pp.81-88
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• 2004

This paper analyzed the proper methods to solve the security problems of establishing trust zone which is changed by security policy in large scale networks containing multiple VPNs. Therefore, we surveyed the vulnerability of VPN technologies, it analyzed various models suitable for trust zone. By simulations of various models, we Propose the cascade perimeter defence policy model having the neit as such an efficient transit cost and the strictly isolation for trust tone. This model can protect the trust zone from the public network by dividing the trust Tone according to each VPN group and it shows the better transit performance by cascading the position of perimeter defence policy.

• International Journal of High-Rise Buildings
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• v.6 no.1
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• pp.1-9
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• 2017

The Pertamina Energy Tower (PET) and Manhattan West North Tower (MWNT) are two supertall towers recently designed and engineered by Skidmore, Owings & Merrill (SOM). The structural system for both buildings consists of an interior reinforced concrete core and a perimeter moment frame system, which is primarily structural steel. As is typical for tall towers with both concrete and steel elements, staged construction analysis was performed in order to account for the long term effects of creep and shrinkage, which result in differential shortening between the interior concrete core and steel perimeter frame. The particular design of each tower represents two extremes of behavior; PET has a robust connection between the perimeter and core in the form of three sets of outriggers, while the perimeter columns of MWNT do not reach the ground, but are transferred to the core above the base. This paper will present a comparison of the techniques used during the analysis and construction stages of the design process with the goal of understanding the differences in structural behavior of these two building systems in response to the long term effects of creep and shrinkage. This paper will also discuss the design and construction techniques implemented in order to minimize the differential shortening between the interior and exterior over the lifespan of these towers.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.10
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• pp.947-955
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• 2005

For the purpose of evaluating the thermal performance for air-barrier air conditioning system in perimeter zone, two air-conditioning systems, conventional perimeter air-conditioning system and air-barrier system, are evaluated and compared by scale model experiment and simulation during cooling season. As a result, measurement shows that supply air velocity of 1 m/s in the upstream direction at perimeter is more effective. Air-barrier system could reduce the cooling energy by $10\sim20\%$ compared with conventional system. Numerical simulation was carried out considering solar effect for reliable result. This method has improved the accuracy of numerical simulation for the space affected by the solar radiation. Both measurement and simulation results show that supply air velocity of 1 m/s at perimeter is the most effective.

• Bulletin of the Korean Mathematical Society
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• v.42 no.3
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• pp.501-507
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• 2005

A Boolean matrix with rank 1 is factored as a left factor and a right factor. The perimeter of a rank-1 Boolean matrix is defined as the number of nonzero entries in the left factor and the right factor of the given matrix. We obtain new characterizations of rank preservers, in terms of perimeter, of Boolean matrices.

• Bulletin of the Korean Mathematical Society
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• v.45 no.2
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• pp.355-363
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• 2008

For a Boolean rank 1 matrix $A=ab^t$, we define the perimeter of A as the number of nonzero entries in both a and b. The perimeter of an $m{\times}n$ Boolean matrix A is the minimum of the perimeters of the rank-1 decompositions of A. In this article we characterize the linear operators that preserve the perimeters of Boolean matrices.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.43-46
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• 2008

In Top-Down construction for underground structures, the placement of slab as a horizontal supporting member against lateral earth pressure is an important process in determining construction time and cost. Usually, a reinforced concrete perimeter girder distributes concentrated lateral loads from earth retaining structures such as Cast-in-place (CIP) piles. By combining the function of the R/C perimeter girder and horizontal slabs, the Opened Slab Method is efficient for reducing construction time by elimination of time-consuming formwork for traditional perimeter girders. The structural performance of the method is also discussed in this paper.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.7
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• pp.62-66
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• 2008

In this paper we have proposed a power aware location based routing protocol for wireless ad hoc network. The existing greedy perimeter stateless routing (GPSR) has some problems which are certain node overloaded and void situation. The proposed power aware greedy perimeter stateless routing (PAGPSR) protocol gives a solution for these problems in GPSR. PAGPSR uses power aware and geographically informed neighbor selection to route a packet towards the destination. It also gives a solution for the fundamental problem in geographical routing called communication void. It considers residual energy of battery and distance to the destination for the next hope node selection. When it encounters a void it starts limited-flooding to select next hop node. To evaluate the performance of our protocol we simulated PAGPSR in ns-2. Our simulation results show that our protocol achieves longer network lifetime compared with greedy perimeter stateless routing (GPSR).

• Journal of the Korea Convergence Society
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• v.9 no.12
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• pp.61-68
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• 2018

As the smartphone and mobile environment develop, the time and space constraints for individual work performance are disappearing. Companies can reduce costs and expand their business quickly through cloud computing. As the use of various cloud expands, the boundaries of users, data, and applications are disappearing. Traditional security approaches based on boundaries (Perimeter) are losing their utility in the cloud environment. This paper describes the limitations of existing network access control (NAC) in a cloud environment and suggests network security technology that complements it. The study explains the SDP and combines SDP(Software Defined Perimeter) to overcome the limitations of NAC, while at the same time explaining its role as a new framework for supporting the cloud environment. The new framework proposed in this paper suggests a software-based network security solution that supports physical and software parts, providing identity-based access control, encrypted segment management, and dynamic policy management, not IP-based.

• Earthquakes and Structures
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• v.23 no.2
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• pp.151-168
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• 2022

Torsion is one of the most important causes of building collapse during earthquakes. Sometimes, despite the symmetric form of the building, infill walls disturb the symmetry of the lateral resisting system. The purpose of this research is to investigate the effect of urban layout on developing torsion caused by infill walls. For this purpose, a typological study was conducted based on the conditions of perimeter walls on 364 buildings and then 9 cases were selected. The dimensions of the selected buildings are constant and the conditions of the perimeter walls including facades with openings and cantilevered facades are variable. The selected buildings with 60 different layouts of infill walls were analyzed and the behavior of each one was evaluated based on the torsional irregularity criteria of seismic codes. The results of the analyses showed that if the perimeter walls of a building are symmetric, asymmetric interior walls will not be important in developing torsion and effective parameters in symmetry of the perimeter infill walls are the number of walls, area of openings, aspect ratio, and construction details. Finally, architectural solutions to mitigate the torsional effects of infill walls were proposed for buildings with solid infill walls on some sides, for buildings where the perimeter walls of one side are on the cantilevered part, and for buildings where the perimeter walls of two adjacent sides are on the cantilevered part. In three-sided buildings, where two adjacent façades are cantilevered, it is often impossible to use the potential of the infill walls.

• Proceedings of the SAREK Conference
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• 2006.11a
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• pp.53-53
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• 2006