• Journal of Korea Multimedia Society
• /
• v.9 no.2
• /
• pp.172-188
• /
• 2006

Sensor localization is one of the fundamental problems in wireless sensor networks. Previous localization algorithms can be classified into two categories, the GGB (Global Geometry-Based) approaches and the LGB (Local Geometry-Based). In the GGB approaches, there are a fixed set of reference nodes of which the coordinates are pre-determined. Other nodes determine their positions based on the distances from the fixed reference nodes. In the LGB approaches, meanwhile, the reference node set is not fixed, but grows up dynamically. Most GGB algorithms assume that the nodes are deployed in a convex shape area. They fail if either nodes are in a concave shape area or there are obstacles that block the communications between nodes. Meanwhile, the LGB approach is vulnerable to the errors in the distance estimations. In this paper, we propose new localization algorithms to cope with those two limits. The key technique employed in our algorithms is to determine, in a fully distributed fashion, if a node is in the line-of-sight from another. Based on the technique, we present two localization algorithms, one for anchor-based, another for anchor-free localization, and compare them with the previous algorithms.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.27 no.3
• /
• pp.38-46
• /
• 2023

In this study, a bearing test was performed and analytically evaluated to evaluate the bearing performance according to the application of the aluminum stiffener in round-end concrete. In the bearing strength test, the change in bearing performance due to the aluminum stiffener using the aluminum form for manufacturing concrete with round-end, and the steel anchor bolts for member movement and assembly was confirmed. The FE analysis model was identically configured to the experimental conditions, and the result was compared with the experiment. Also, the crack patterns and stress behavior were confirmed. In addition, the effect of strength change of the aluminum stiffener on the round-end concrete was also evaluated analytically. The bearing strength of the round-end concrete increased by about 20% due to the aluminum stiffener, and it was confirmed that the steel anchor bolt did not affect the bearing strength. The maximum load and crack patterns shown as a result of FE analysis were similar to those of the experiment. As a result of FE analysis according to the strength change of the aluminum stiffener, the maximum load change according to the increase and decrease of the strength of the aluminum stiffener by 10% and 20% was evaluated to have no significant effect at a maximum of about 4% compared to before the strength change.

• Journal of the Korean Geotechnical Society
• /
• v.36 no.11
• /
• pp.51-60
• /
• 2020

Estimation of passive earth pressure is an important factor in anchor block, temporary retaining wall and support block of raker that resist lateral earth pressure. In practice, due to ease of use, it is common to estimate the earth pressure using the theory of Coulomb and Rankine, which assumes the failure plane as a straight line. However, the passive failure plane generated by friction between the wall surface and the soil forms a complex failure plane: a curve near the wall and a flat plane near the ground surface. In addition, the limit displacement where passive earth pressure is generated is larger compared to where the active earth pressure is generated. Thus, it is essential to calculate the passive earth pressure that occurs at the allowable displacement range in order to apply the passive earth pressure to the design for structural stability reasons. This study analyzed the mobilized passive earth pressured to various displacement ranges within the passive limit displacement range using the semi-empirical method considering the complex failure plane.

• Journal of Broadcast Engineering
• /
• v.16 no.6
• /
• pp.1069-1072
• /
• 2011

This paper proposes the method which reduces complexity and improves coding efficiency by solving a problem of HEVC bi-prediction. In current HM 3.0, it is frequently occurred that L0 motion information and L1 motion information are identical in blocks which are bi-predicted. In this case, L1 motion vector is replaced by non-zero motion vector which belongs to first available neighbor block of current block. If they are still identical, prediction mode is replaced by uni-prediction. As an experimental result, in LD(Low-Delay) case, decoding time is reduced roughly 2%~5% and coding gain is roughly 0.3%~0.5% compared with the HM 3.0 anchor.

• Korean Institute of Interior Design Journal
• /
• v.18 no.6
• /
• pp.202-210
• /
• 2009

This research was undertaken to prove the relationship between street mall activation and architectural plan design. The research methodology was established based on the analysis of data of two existing street malls in Korea (Western Dome & LaFesta) and theoretical studies of outdoor space design. The findings from this study are the following: First, building blocks with segments in every 50m or so are ideal for detailed communication between visitors and building contents. Second, the ratio of width of main corridor and building height should be less than 1 to provide intimate feel and keep visitors' attention concentrated in the facility. Third, store unit should have more storefronts to be exposed more to passers-by and lead more pedestrian traffic. Fourth, shape of store unit would rather be wide and shallow, instead of narrow and deep, to have more exposure to the central corridor. Fifth, the building block of the busiest(most expensive) area that is usually at the main entrance area of street mall should be flexible to fit more smaller units to maximize the profitability. Sixth, the main entrance of store should face the main pedestrian corridor to induce the influx of visitors. Lastly seventh, anchor tenant that has strong name recognition is usually located on basement or higher level to induce pedestrian traffic into the mall, key tenants that are strong and familiar brand names should be located at the corner of building block with spacing to attract visitors, provide even distribution of traffic, and support wayfinding, and local tenant should be located at small units along the central corridor or remainder spaces occurred from building core layout.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.8
• /
• pp.1250-1256
• /
• 2017

In this research, a high-performance ultrasonic positioning system is proposed to track the positions of an indoor mobile object. Composed of an ultrasonic sender (mobile object) and a receiver (anchor), the system employs three ultrasonic time-off-flights (TOFs) and trilateration to estimate the positions of the object with an accuracy of sub-centimeter. On the other hand, because ultrasonic waves are interfered by temperature, wind and various obstacles obstructing the propagation while propagating in air, ultrasonic pulse debounce technique and Kalman filter were applied to TOF and position calculation, respectively, to compensate for the interference and to obtain more accurate moving object position. To perform tasks in real time, ultrasonic signals are processed full-digitally with a Zynq SoC, and as a software design tool, Vivado IDE(integrated design environment) is used to design the whole signal processing system in hierarchical block diagrams. And, a hardware/software co-design is implemented, where the digital circuit portion is designed in the Zynq's fpga and the software portion is c-coded in the Zynq's processors by using the baremetal multiprocessing scheme in which the c-codes are distributed to dual-core processors, cpu0 and cpu1. To verify the usefulness of the proposed system, experiments were performed and the results were analyzed, and it was confirmed that the moving object could be tracked with accuracy of sub-cm.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.2109-2112
• /
• 2007

독도는 울릉도에서도 동남쪽으로 약 87.4km 떨어져 외해의 영향을 많이 받고 있는 지역이지만 방파제 등 외곽시설이 전무하여 평상파랑에도 접안이 어려운 경우가 많아서 독도 관광자원 활용도 및 편의시설 제공면에서 많은 어려움이 있다. 이에 본 연구에서는 독도 접안시설의 전면에 최근 국내에 본격적으로 도입되고 있는 부방파제(floating breakwater)를 설치할 경우 고정식 방파제 설치에 따른 문제점을 충분히 개선할 수 있다고 판단하여, 부방파제 설치에 따른 기술적인 타당성과 부두 이용률 개선효과 등을 연구 하였다. 독도의 접안시설은 해역이 동도와 서도에 의해 북쪽은 일부 차폐되고 남쪽은 직접 노출되어 있는 지리적 특성이 있어 주 파향인 남쪽계열의 8개 파향(SE, SSE, S, SW, SSW, WSW, W, WNW)의 평상파 제어가 가능하도록 방파제를 배치하였고, 이에 따른 부두 이용률 검토결과 부방파제를 설치할 경우 남쪽계열 파랑에 대하여 현상태에 비하여 부두 이용률이 대략 2배정도 증가되는 것으로 나타났으며, 부방파제 계류시스템의 안정에 대해서도 부체에 영향을 주는 외력에 대하여 계류체인의 길이와 Anchor Block 자중의 규모를 적당히 조정하면 충분히 안정한 것으로 검토되었다.

• Nuclear Engineering and Technology
• /
• v.56 no.2
• /
• pp.485-497
• /
• 2024

Ring beam is the main anchorage zone of the tendons in the nuclear power prestressed concrete containment vessel (PCCV). Its safety is crucial and has a great influence on the overall performance of PCCV. In this paper, two half-scale ring beams were tested to investigate the mechanical performance of the anchorage zone in the PCCV under multidirectional pressure. The effect of working condition with different tension sequences was investigated. Additionally, a half axisymmetric plane model of the containment was established by the finite element simulation to further predict the experimental responses and propose the local reinforcement design in the anchorage zone of the ring beam. The results showed that the ultimate load of the specimens under both working conditions was greater than the nominal ultimate tensile force. The original reinforcement design could meet the bearing capacity requirements, but there was still room for optimization. The ring beam was generally under pressure in the anchorage area, while the splitting force appeared in the under-anchor area, and the spalling force appeared in the corner area of the tooth block, which could be targeted for local strengthening design.

• Journal of the Korean Institute of Educational Facilities
• /
• v.20 no.2
• /
• pp.3-14
• /
• 2013

The purpose of this study is to analyze patterns of public school building layout types, open space and relationship with communities in the Manhattan grid plan. The study illustrates how building layout patterns of school facilities are influenced by societal demands in the urban grid environment. During the nineteenth century, the Island of Manhattan was transformed into a physical representation of the Cartesian coordinate system via the development of the grid street plan. In order to take advantage of streets as urban space, it is quite important to understand characteristics of communities and open space relationships between buildings and streets. Moreover, the strategic planning of schools' outdoor space vitalizes public streets as a critical community anchor. This research reviews 118 Manhattan public schools and categorizes them by (1) building layout type, (2) site type, (3) circulation and public open space, which are the biggest factors that determine the layout patterns of the public schools in Manhattan. As a result of analysis, the layout patterns are classified into seven types : "ㅡ", "L", "ㄷ", "ㅁ", "H", "T" and "other" type. Of these, "ㅡ" type and "L" type occur most frequently, because these configurations most flexibly fit into the limited grid-locked blocks, the various types of site & topography, and adapt most dynamically to the open spaces created by using avenues and streets. The ultimate objective of this study is to provide a case study for future efforts to plan open spaces for campuses that effectively utilize the streets in proximity.

• Journal of KIISE:Computer Systems and Theory
• /
• v.37 no.1
• /
• pp.8-18
• /
• 2010

Traditional storage server suffers from duplicated data blocks which cause an waste of storage space and network bandwidth. To address this problem, various de-duplication mechanisms are proposed. Especially, lots of works are limited to backup server that exploits Contents-Defined Chunking (CDC). In backup server, duplicated blocks can be easily traced by using Anchor, therefore CDC scheme is widely used for backup server. In this paper, we propose a new de-duplication mechanism for improving a storage system. We focus on efficient algorithm for supporting general purpose de-duplication server including backup server, P2P server, and FTP server. The key idea is to adapt stride scheme on traditional fixed block duplication checking mechanism. Experimental result shows that the proposed mechanism can minimize computation time for detecting duplicated region of blocks and efficiently manage storage systems.