• Database Research
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• v.34 no.3
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• pp.69-85
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• 2018

Many researches proposed federated query engines to perform query on several homogeneous or heterogeneous datasets simultaneously that significantly improve the quality of query results. The existing techniques allow querying only over a few heterogeneous datasets considering the static binding using the non-standard query. However, we observe that a simultaneous system considering the integration of heterogeneous metadata standards can offer better opportunity to generalize the query over any homogeneous and heterogeneous datasets. In this paper, we propose a transparent federated engine (DRAZ) to query over multiple data sources using SPARQL. In our system, we first develop the ontology for a non-RDF metadata standard based on the metadata kernel dictionary elements, which are standardized by the metadata provider. For a given SPARQL query, we translate any triple pattern into an API call to access the dataset of corresponding non-RDF metadata standard. We convert the results of every API call to N-triples and summarize the final results considering all triple patterns. We evaluated our proposed DRAZ using modified Fedbench benchmark queries over heterogeneous metadata standards, such as DCAT and DOI. We observed that DRAZ can achieve 70 to 100 percent correctness of the results despite the unavailability of the JOIN operations.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.13-18
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• 2022

In this paper, we proposed VW-FedAVG(Validation based Weighted FedAVG) which updates the global model by weighting according to performance verification from the models of each device participating in the training. The first method is designed to validate each local client model through validation dataset before updating the global model with a server side validation structure. The second is a client-side validation structure, which is designed in such a way that the validation data set is evenly distributed to each client and the global model is after validation. MNIST, CIFAR-10 is used, and the IID, Non-IID distribution for image classification obtained higher accuracy than previous studies.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.666-669
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• 2024

연합학습은 원본 데이터를 공유하지 않고 모델을 학습할 수 있는 각광받는 프라이버시를 위한 학습방법론이다. 이를 위해 참여자의 데이터를 수집하는 대신, 데이터를 인공지능 모델 학습의 요소들(가중치, 기울기 등)로 변환한 뒤, 이를 공유한다. 이러한 강점에 더해 기존 연합학습을 개선하는 방법론들이 추가적으로 연구되고 있다. 기존 연합학습은 모델 가중치를 평균내는 것으로 참여자 간에 동일한 모델 구조를 강요하기 때문에, 참여자 별로 자신의 환경에 알맞은 모델 구조를 사용하기 어렵다. 이를 해결하기 위해 지식 증류 기반의 연합학습 방법(Knowledge Distillation-based Federated Learning)으로 서로 다른 모델 구조를 가질 수 있도록(Model Heterogenousity) 하는 방법이 제시되고 있다. 연합학습은 여러 참여자가 연합하기 때문에 일부 악의적인 참여자로 인한 모델 포이즈닝 공격에 취약하다. 수많은 연구들이 기존 가중치를 기반으로한 연합학습에서의 위협을 연구하였지만, 지식 증류 기반의 연합학습에서는 이러한 위협에 대한 조사가 부족하다. 본 연구에서는 최초로 지식 증류 기반의 연합학습에서의 모델 성능 하락 공격에 대한 위협을 실체화하고자 한다. 이를 위해 우리는 GMA(Gaussian-based Model Poisoning Attack)과 SMA(Sign-Flip based Model Poisoning Attack)을 제안한다. 결과적으로 우리가 제안한 공격 방법은 실험에서 최신 학습 기법에 대해 평균적으로 모델 정확도를 83.43%에서 무작위 추론에 가깝게 떨어뜨리는 것으로 공격 성능을 입증하였다. 우리는 지식 증류 기반의 연합학습의 강건성을 평가하기 위해, 새로운 공격 방법을 제안하였고, 이를통해 현재 지식 증류 기반의 연합학습이 악의적인 공격자에 의한 모델 성능 하락 공격에 취약한 것을 보였다. 우리는 방대한 실험을 통해 제안하는 방법의 성능을 입증하고, 결과적으로 강건성을 높이기 위한 많은 방어 연구가 필요함을 시사한다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.559-562
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• 2004

The methodologies to develop land use plans are divided into two different ways, top-down and bottom-up planning. The bottom-up method is more efficient and effective to detailed land use planning. However, it requires considerable amount of information about the present status of land use. Cadastral information system is one of the best information provider for the planning. Building Register Database shows the type, area, use and location of a building. Both cadastral and Building Register systems apparently contain useful information needed to the physical planning. The study focuses on developing a prototype to provide real time information for detailed physical planning by a federated database system using the two databases.

• Animal Systematics, Evolution and Diversity
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• v.30 no.2
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• pp.108-118
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• 2014

Micronesia is an island nation located north of Papua New Guinea in the Pacific Ocean. A survey was conducted on Chuuk, which is one of the four main islands of Micronesia, from 11-25 Nov 2012. Echinoderms collected at one intertidal area as well as at 16 SCUBA diving points of 10-40 m depths in the subtidal zone were identified based on morphological characteristics. In total, 35 species from 165 individuals were identified: two crinoids, eight asteroids, four ophiuroids, seven echinoids, and 14 holothuroids. Among them, one asteroid, one ophiuroid, one echinoid, and two holothuroids were newly recorded from Micronesia.

• ALGAE
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• v.28 no.3
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• pp.241-266
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• 2013

The mangrove algal flora of Guam and the Federated States of Micronesia has been poorly explored. We add to our knowledge of this region by observations of collections from these regions. This paper presents new and additional records of: Rhodophyta-Acrochaetium globosum, Colaconema sp., Caulacanthus indicus, Bostrychia moritziana / B. radicans, B. radicosa, B. simpliciuscula, B. kelanensis and B. tenella, Murrayella periclados, and Caloglossa ogasawaraensis; Chlorophyta-Boodleopsis carolinensis; and Phaeophyceae-Dictyota adnata, Dictyotopsis propagulifera, and Canistrocarpus cervicornis. Most specimens were cultured to investigate their reproductive biology and many specimens were further identified using molecular data. Low molecular weight carbohydrates (dulcitol, sorbitol, and digeneaside) were identified in samples of B. radicosa and B. simpliciuscula. We also present data on manganese-rich deposits found on B. simpliciuscula and B. tenella in culture, possibly formed by epiphytic bacteria.

• Journal of Korean Library and Information Science Society
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• v.37 no.2
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• pp.127-144
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• 2006

This study intends to analyze the integrated search methods in digital libraries environment. To categorize various integration methods, I investigated the developmental properties and integration types of digital libraries from a users point of view. And then, I reviewed the current best practices of library portal which are JISC Information Environment, NSDL OCKHAM and Korea Knowledge Portal Initiatives. Nextly, I derived the two methods of Integrated search mechanisms such as aggregated search and distributed search that is useful in the digital libraries environment.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.155-161
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• 2001

Federated process framework is introduced responding to market\\`s needs to gain benefits of process information sharing in a virtual enterprise. The framework is verified by implementing its prototype system. However, it is very difficult to integrate developed prototype system with operating legacy systems to show its applicability. Thus, a test bed approach is widely adopted to provide a system environment that imitates the operations of real legacy systems and their interactions. In this paper, we described implementation detail of test bed imitating the real-world workflow systems. We also show its contribution and results of the prototype system that was implemented on the test bed.

• Journal of Ecology and Environment
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• v.33 no.2
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• pp.79-94
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• 2010

This article focused on the environmental changes on atolls in Micronesia. First, we considered the problem. Second, we designed research that focused on the impacts of environmental changes especially in relation to globalization and global warming in the Federated States of Micronesia (FSM). The results were in accordance to the hypotheses that globalization had impacted prominently in communities on main islands and impact was lessened with increased distance from the centre. The fact that the islands are remotely situated and thus, in theory, do not have much outside influence, has not alleviated them from having societal concerns. The earth's environmental change is causing an impact on the main islands as well. This has been governed by distinctive characteristics in their geographical, regional, and contents. Moreover, they showed stronger concerns about impacts on the environment than globalization. A set of questionnaires was used as the principal assessment method to quantify the concerns relating to the environmental changes.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.211-211
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• 2000

The multiple targets tracking problem has been one of main issues in the radar applications area in the last decade. Besides the standard Kalman filtering, various methods including the variable dimension filter, input estimation filter, interacting multiple model (IMM) filter, federated variable dimension filter with input estimation, probable data association (PDA) filter etc. have been proposed to address the tracking and sensor fusion issues. In this paper, two existing tracking algorithms, i.e. the IMMPDA filter and the variable dimension filter with input estimation (VDIE), are combined for the purpose of improving the tracking performance of maneuvering targets in clutter. To evaluate the tracking performance of the proposed algorithm, three typical maneuvering patterns i.e. Waver, Pop-Up, and High-Diver motions, are defined and are applied to the modified IMMPDA filter considered as well as the standard IMM filter. The smaller RMS tracking errors, in position and velocity, of the modified IMMPDA filter than the standard IMM filter are demonstrated through computer simulations.