• Korean Journal of Remote Sensing
• /
• v.28 no.1
• /
• pp.55-67
• /
• 2012

Real-time image georeferencing is required to generate spatial information rapidly from the image sequences acquired by multi-sensor systems. To complement the performance of position/attitude sensors and process in real-time, we should employ on-line aerial triangulation based on a sequential estimation algorithm. In this study, we thus attempt to derive an efficient on-line aerial triangulation algorithm for real-time georeferencing of image sequences. We implemented on-line aerial triangulation using the existing Given transformation update algorithm, and a new inverse normal matrix update algorithm based on observation classification, respectively. To compare the performance of two algorithms in terms of the accuracy and processing time, we applied these algorithms to simulated airborne multi-sensory data. The experimental results indicate that the inverse normal matrix update algorithm shows 40 % higher accuracy in the estimated ground point coordinates and eight times faster processing speed comparing to the Given transformation update algorithm. Therefore, the inverse normal matrix update algorithm is more appropriate for the real-time image georeferencing.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.3
• /
• pp.159-159
• /
• 2004

With the increasing number of subscribers in the mobile communication, the reduction of the cell size and the increment of roaming frequency have increased the cost of location management. In order to reduce the cost of location management, we propose a new strategy of location management. In this scheme, whether the terminal executes location update or not is decided both by the call arrival probability in a new LA and by the number of location updates which are unexecuted despite that the terminal moved into a new LA. The call arrival probability is computed using the predicted information about the terminal mobility pattern. We simulated to evaluate our strategy's performance. In the high mobility prediction level, this scheme reduces the cost of location update considerably. Even though it is in the low mobility prediction level, the cost does not exceed that of IS-41 at most. This scheme also showed better performance, compared with that of AS(Alternative Strategy) which requires an overhead such as predicted information maintenance.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.3
• /
• pp.1-8
• /
• 2004

With the increasing number of subscribers in the mobile communication, the reduction of the cell size and the increment of roaming frequency have increased the cost of location management. In order to reduce the cost of location management, we propose a new strategy of location management. In this scheme, whether the terminal executes location update or not is decided both by the call arrival probability in a new LA and by the number of location updates which are unexecuted despite that the terminal moved into a new LA. The call arrival probability is computed using the predicted information about the terminal mobility pattern. We simulated to evaluate our strategy's performance. In the high mobility prediction level, this scheme reduces the cost of location update considerably. Even though it is in the low mobility prediction level, the cost does not exceed that of IS-41 at most. This scheme also showed better performance, compared with that of AS(Alternative Strategy) which requires an overhead such as predicted information maintenance.

• The KIPS Transactions:PartC
• /
• v.13C no.1 s.104
• /
• pp.121-128
• /
• 2006

In Mobile IPv6, a handover latency is an important issue. To reduce the handover latency, mipshop working group in IETF has studied the fast handover(FMIPv6) which creates and verifies a new care-of address(NCoA) in advance before a layer 2 handover resulting in reduced handover latency. Even in FMIPv6, the NCoA must be registered in a home agent(HA). This registration still creates a significant amount of delay. To reduce registration latency, we propose a tentative and early binding update(TEBU) scheme that the NCoA is registered in the HA in advance during the layer 2 handover based on FMIPv6. We use cost analysis for the performance evaluation. As a result, we found that the TEBU scheme guarantees lower handover latency than FMIPv6 as much as approximately 21%.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.4
• /
• pp.85-91
• /
• 2019

In this paper, we propose a new logging and recovery scheme that is suited for the high-performance transaction processing system base on flash memory storage. The proposed scheme is designed by considering flash's I/O characteristic of asymmetric costs between page update/read operations. That is, we substitute the costly update operation with writing and real-time usage of snapshot log, which is for the page-level physical redo. From this, we can avoid costly rewriting of a dirty page when it is evicted form a buffering pool. while supporting efficient revery procedure. The proposed scheme would be not lucrative in the case of HDD-based system. However, the proposed scheme offers the performance advance sush as a reduced number of updates and the fast system recovery time, in the case of flash storage such as SSD (solid state drive). Because the proposed scheme can easily be applied to existing systems by saving our snapshot records and ordinary log records together, our scheme can be used for improving the performance of upcoming SSD-based database systems through a tiny modification to existing REDO algorithms.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.5
• /
• pp.23-31
• /
• 2010

With the advances in the information technology and mobile communications, we now face increasing demands for various services based on both of position tracking of moving objects and their efficient index scheme. Accordingly, the $TPR^*$-tree, which were proposed for efficiently tracking moving objects and predicting their positions in the future time, has drawn much intention. As the $TPR^*$-tree came from the R-tree that is suitable for indexing static objects, it does not support cheap update costs. Therefore, it seems to be very costly to index moving objects if there are frequent occurrences of node updates caused by continuously changing velocities and positions. If some moving objects with high velocities have node updates, in particular, then the $TPR^*$-tree may suffer from many unnecessary updates in the wide range of tree regions. To avoid such a problem, we propose a method that can keep fast-moving objects in the child nodes of the root node, thereby saving node update costs in the $TPR^*$-tree. To show our performance advantages and retaining $TPR^*$-tree features, we performed some performance experiments using a simulation technique.

• The Journal of the Acoustical Society of Korea
• /
• v.41 no.2
• /
• pp.199-209
• /
• 2022

Typical anomaly detection algorithms are trained by using prior data. Thus the batch learning based algorithms cause inevitable performance degradation when characteristics of newly incoming normal data change over time. We propose an online anomaly detection algorithm which can consider the gradual characteristic changes of incoming normal data. The proposed algorithm based on one-class classification model includes both offline and online learning procedures. In offline learning procedure, the algorithm learns the prior data to be close to centroid of the latent space and then updates the centroid of the latent space incrementally by new incoming data. In the online learning, the algorithm continues learning by using the updated centroid. Through experiments using public underwater acoustic data, the proposed online anomaly detection algorithm takes only approximately 2 % additional learning time for the incremental centroid update and learning. Nevertheless, the proposed algorithm shows 19.10 % improvement in Area Under the receiver operating characteristic Curve (AUC) performance compared to the offline learning model when new incoming normal data comes.

• The KIPS Transactions:PartD
• /
• v.13D no.4 s.107
• /
• pp.477-490
• /
• 2006

Existing index structures need very much update cost because they repeat delete and insert operations in order to update continuously moving objects. In this paper, we propose a new index structure which reduces the update cost of continuously moving objects. The proposed index structure consists of a space partitioning index structure that stores the location of the moving objects and an auxiliary index structure that directly accesses to their current positions. In order to increase the fanout of the node, it stores not the real partitioning area but kd-tree as the information about the child node of the node. In addition, we don't traverse a whole index structure, but access the leaf nodes directly and accomplish a bottom-up update strategy for efficiently updating the positions of moving objects. We show through the various experiments that our index structure outperforms the existing index structures in terms of insertion, update and retrieval.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2002.04a
• /
• pp.7-10
• /
• 2002

실체뷰는 질의 처리 성능 향상을 위한 수단으로 널리 연구되어 왔다. 이러한 실체뷰는 하부 데이타가 변경되었을 경우에 일관성을 유지해야 하는데, 그 기법으로는 뷰를 하부 데이타로부터 재생성하는 방법과 변경 내용 중 뷰와 관련 있는 것만 반영하는 점진적 갱신이 있다. 최근 XML 이라는 웹 문서 표준이 대두되면서 여러 응용 분야에서 이를 활용 하려는 노력이 진행 중이다. 본 논문에서는 XML문서를 대상으로 하는 XML 실체뷰를 지원하는 XML 저장 시스템의 구현과, 구현된 시스템을 대상으로 실체뷰를 재생성하는 방법과 점진적으로 갱신하는 기법의 성능을 비교 평가한 결과를 기술한다.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2005.11a
• /
• pp.133-138
• /
• 2005

This study is about the description method & scope of maintenability in window components which have been applied to the remodelling work in Apartment Housing. Already we did established the maintenability performance index through the preceding research in recent. It is defined as changeability, prefabrication, coordination. and capacity of performance preservation. As the results of analysys on the performance information that is reported by catalog & internet media, the ratio of adaptation as a maintenabilty performance was revealed to percentage of 11(11%). And as the respects of represented content, majority of the performance information only have dealt with advertising-effect, rather than physical performance make easy to change and separat.