• Journal of the Korea Society of Computer and Information
• /
• v.25 no.10
• /
• pp.51-58
• /
• 2020

The DDS discovery is a behind-the-scenes way in which DDS objects on different nodes find out each other in a same domain. If the DDS discovery takes a long time, the preparation time for DDS communication is also delayed. And if the DDS discovery between several nodes fails, DDS communication between nodes related to them would be also failed. This problems can be a big cause of overall system performance degradation. Therefore, the improvement of performance for the DDS discovery gives the effect that improves the performance of the entire system. In this paper, I propose an efficient new method which improves the performance and reduces the time of DDS discovery. I simulate both the origin and the new proposed method for DDS discovery, and I compare the result of performance. This result will help for improving a DDS discovery in a large-scale system.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.11
• /
• pp.1554-1561
• /
• 2018

This paper surveys the DDS, a real - time communication middleware, and proposes ways to improve the DDS secure communication performance. DDS is a communication middleware standard by the OMG. The OMG has released the DDS Security standard to resolve the security issues. The security performance of DDS can be considered into transmission speed and confidentiality. In terms of confidentiality, AES-GCM, currently the encryption algorithm specified by DDS Security, is a very strong encryption algorithm, but there are well known weaknesses associated with authentication. In terms of speed, The computational load for the security function is a restriction to use DDS in systems which requires real-time performance. Therefore, in order to improve the DDS security, algorithms that are faster than AES-GCM and strong in encryption strength are needed. In this paper, we propose a DDS message encryption method applying AES-OCB algorithm to meet these requirements and Compared with the existing DDS, the transmission performance is improved by up to 12%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.12
• /
• pp.1243-1250
• /
• 2014

In this paper, a wideband DDS module covering the frequency range from 0.5 to 1.1 GHz was designed and fabricated. The clock frequency of the DDS was selected 2.4 GHz in order for 600 MHz output bandwidth. Multiple spurious cancelling signals having same amplitude and $180^{\circ}$ phase difference compared to the spurious were created at the additional path and added to the output signal within DDS for the spurious performance improvement. The fabricated DDS module showed better spurious performance than the commercial DDS one more than 10 dB and frequency tuning time was 340 ns below.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.05a
• /
• pp.363-366
• /
• 2014

OMG 그룹에서 제안하고 있는 DDS(Data Distribution Service) 미들웨어에서 디스커버리 프로토콜은 미들웨어 간의 상호 운용성 지원을 위한 기본 요소이다. DDS 미들웨어가 적용되는 대부분의 환경에서는 다수의 노드에서 생성된 참여자를 찾기 위해 한꺼번에 많은 수의 디스커버리 정보가 교환되기 때문에 노드 및 네트워크의 성능에 많은 영향을 미친다. 본 논문에서는 DDS 미들웨어 개발 후에 시험이 되어야 하는 디스커버리 기능의 검증과 성능 측정을 위한 응용을 설계하고 이를 구현하였다. 디스커버리 시험 응용은 디스커버리 시험 전체를 관리하는 제어 응용, DDS 미들웨어를 통하여 DDS 개체를 생성하고 이들간의 정보교환을 담당하는 DDS 응용, 그리고 DDS 응용을 통제하고 실행 결과를 수집하여 제어 응용으로 전송하는 데몬 서버로 구성된다. 구현된 디스커버리 시험 응용은 디스커버리 기능 검증 및 성능 정보의 수집을 프로세서 간의 통신을 통하여 효과적으로 수행한다. 또한, DDS 응용의 동작 권한을 제어 응용이 위치한 노드에 집중시킴으로써 많은 수의 노드에서 시험이 필요한 환경에 적합하도록 설계되었다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2015.10a
• /
• pp.314-316
• /
• 2015

데이터 분배 서비스(DDS)는 객체 관리 그룹(OMG)에서 정의한 미들웨어 규격으로, 분산 네트워크 상에서 표준화 된 데이터 분배를 위한 응용프로그램 인터페이스(API)를 정의하고 있다. NeoDDS는 OMG DDS 규격을 준수하는 국산 DDS 미들웨어이다. 본 논문에서는 DDS 시스템의 개발 단계에서 DDS 시스템의 동작을 시뮬레이션 해 볼 수 있도록 지원하는 NeoDDS 기반의 시뮬레이터인 NeoSim의 구조와 동작방식에 대해 소개한다.

• Journal of KIISE
• /
• v.44 no.5
• /
• pp.449-459
• /
• 2017

Data Distribution Service (DDS) is a communication middleware that supports a flexible, scalable and real-time communication capability. This paper describes several techniques to improve the performance of DDS middleware. Detailed events for the internal behavior of the middleware are defined. A DDS message is disassembled into several submessages of independent, meaningful units for event-driven structuring in order to reduce the processing complexity. The proposed technique of history cache management is also described. It utilizes the fact that status access and random access to the history cache occur more frequently in the DDS. These methods have been implemented in the EchoDDS, the DDS implementation developed by our team, and it showed improved performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.93-96
• /
• 2017

DDS (Data Distribution Serivce) communication middleware is spreading to various private sector as well as the defense sector because it can obtain a very high application effect in a complex system environment in which a plurality of data producers and data consumers are connected by a network. However, application development using DDS middleware is an inefficient structure with a lot of repetitive codes because most users perform 1: 1 mapping with the message they want to exchange. Accordingly, the user has to perform unnecessary repetitive tasks as the topic increases. Therefore, a development support tool that identifies a series of processes required for using DDS middleware and automatically generates the classes that are repeated by Topic is required. In this paper, we propose a method for DDS communication by automatically generating a common class for efficient use of DDS middleware.

• Journal of Korean society of Dental Hygiene
• /
• v.19 no.1
• /
• pp.141-149
• /
• 2019

Objectives: To investigate the real-world re-use of disposable dental supplies (DDS) in dental offices and assess the relationship between general characteristics of dental hygienists and reuse of DDS, with respect to infection control characteristics. Methods: A questionnaire was administered to 277 dental hygienists to assess their general characteristics, awareness of infection control/DDS management, and re-use of DDS. Nine DDS were categorized into the following categories based on their purpose: Critical, Semicritical, Noncritical, and Personal protective equipment (PPE). The association between general characteristics of dental hygienists and re-use of DDS, with respect to infection control characteristics, was assessed using the chi-squared test. Results: All 9 DDS were re-used to different extents. The highest reuse rate of supplies were for masks (64.6%), prophylaxis cups (61.0%) and plastic saliva ejectors (30.0%). Overall, 89.5% of the participants re-used DDS; subgroup analysis showed the following proportions of specific DDS re-use: PPE 66.4%; Semicritical DDS 63.9%; Noncritical DDS 19.5%; and Critical DDS 1.8%. Based on the type of clinic, the rate of re-use was higher in dental clinics than dental hospitals. Thus, the re-use of DDS may be caused by inappropriate or nonexistent guidelines or habitual practice, rather than the awareness or attitude of dental hygienists. Conclusions: In order to ensure a safe environment within the dental clinic, DDS classifications must be clearly outlined in the dental infection control guidelines; moreover, additional studies are needed regarding the regulations for DDS re-use and disposal.

• Textile Coloration and Finishing
• /
• v.30 no.3
• /
• pp.180-189
• /
• 2018

To study the effect of stereoisomeric structures of curing agents on curing behaviors, thermal and mechanical properties of epoxy resins, DGEBA(diglycidyl ether of bisphenol A) epoxy resin and 3,3'- and 4,4'-DDS(diaminodiphenyl sulfone) curing agents were selected. The curing initiation temperature and activation energy of DGEBA/3,3'-DDS was lower than DGEBA/4,4'-DDS. DGEBA/3,3'-DDS has a faster curing rate and higher degree of cure than DGEBA/4,4'-DDS, suggesting that 3,3'-DDS has higher reactivity than 4,4'-DDS. Tensile strength and fracture toughness of DGEBA/3,3'-DDS was lower than those of DGEBA/4,4'-DDS, indicating that mechanical properties of the epoxy resin can be different only by the stereoisomeric difference in chemical structure of the curing agent.

• Applied Chemistry for Engineering
• /
• v.1 no.2
• /
• pp.124-132
• /
• 1990

In order to improve the mechanical properties and fracture toughness of HPT 1071/DDS system, poly(aryl etherimide) (PEI) was incorporated in the resin system. In HPT 1071/DDS system, mechanical properties of cured epoxy resins were not strongly dependent on the concentration of DDS curing agent strongly. In the case of HPT 1071/DDS/PEI system, the fracture toughness and flexural properties of epoxy resins increased with increasing the concentration of PEI. SEM micrographs of cured epoxy resin indicated that the phase separation occured at the low concentration of PEI in this system. In addition, investigation of the relationship between mechanical properties and the morphology of modified epoxy resin was undertaken in HPT 1071/DDS/PEI system.