• Proceedings of the IEEK Conference
• /
• 2003.07b
• /
• pp.803-806
• /
• 2003

본 논문에서는 traceback 동작 없이 decoding이 가능한 Modified Register Exchange 방식을 이용하여 이를 block decoding에 적용하는 비터비 decoding 방식을 제안하였다. Modified Register Exchange 방식을 block decoding에 적용함으로써 decision bit 들을 결정하기 위해 필요한 동작 사이클을 줄였고, block decoding을 사용하는 기존의 비터비 디코더보다 더 적은 latency 가지게 되었다. 뿐만 아니라, 메모리를 더 효율적으로 사용할 수 있으면서 하드웨어의 구현에 있어서도 복잡도가 더 감소하게 된다. 제안된 방식은 같은 하드웨어 복잡도로도 메모리의 감소 또는 latency 의 감소에 중점을 둔 설계가 가능하다.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.40 no.1
• /
• pp.36-44
• /
• 2003

This paper proposes a Viterbi decoding scheme without trace-back operations to reduce the amount of memory storing the survivor path information, and to increase the decoding speed. The proposed decoding scheme is a modified register exchange scheme, and is verified by a simulation to give the same results as those of the conventional decoders. It is compared with the conventional decoding schemes such as the trace-back and the register exchange scheme. The memory size of the proposed scheme is reduced to 1/(5 x constraint length) of that of the register exchange scheme, and the throughput is doubled compared with that of the trace-back scheme. A decoder with a code rate of 2/3, a constraint length, K＝3 and a trace-back depth of 15 is designed using VHDL and implemented in an FPGA. It is also shown that the modified register exchange scheme can be applied to a block decoding scheme.

• Korean Journal of Computational Design and Engineering
• /
• v.18 no.4
• /
• pp.267-274
• /
• 2013

This study focuses on the data schema and data content, which includes maintenance data, data structures and illustration data relevant with the maintenance process of ship and offshore structures. Product lifecycle management (PLM) is expected to encompass all the product data generated for the operation and maintenance information as well as the design and production. This paper introduces a data exchange schema in PLM of ship and offshore, serving as the basis for the role of standards required by the middle-of-life PLM. Also this paper identifies a typology of standards relevant to PLM that addresses the schema of evolving standards and identifies a XML schema supporting the exchange of data related with maintenance operations. Technical document based on standards in accordance with S1000D and Shipdex is explained. A case study illustrating the use of standard data exchange and technical document is presented.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2006.07a
• /
• pp.265-265
• /
• 2006

• IEMEK Journal of Embedded Systems and Applications
• /
• v.5 no.1
• /
• pp.18-22
• /
• 2010

In real-time embedded systems, the responsibility is the most important thing because it is related to human life. Context switching is a part of which can slow down the responsibility. We therefore should minimize the amount of state that needs to be saved during context switching. In this paper, we introduce a new architecture (Register Farm) for context switching which can exchange two contexts in one cycle time. Although it might increase the cost of MCU design and the complexity of circuit, it cannot miss any interrupt during context switching. Consequently, Register Farm architecture can make embedded systems spread out in human life because it can increase reliability and responsibility in real time embedded systems.

• Journal of Advanced Research in Ocean Engineering
• /
• v.4 no.3
• /
• pp.96-104
• /
• 2018

The importance of data management for the efficient maintenance and operation of offshore structures is becoming increasingly important. This paper has discussed the data schema and business rules that standardize the data exchange between ship design, operation and maintenance. Technical documentation that meets the international standards of ShipDex and S1000D for exchanging the operation and management data in neutral or standard formats has been introduced into the life cycle management of ships. The schema of the data exchange is represented by XML (eXtensible Markup Language) and the lifecycle data is implemented by a structured document. Lifecycle data is represented as data modules defined by XML schema. Given the feasible data generation, an example of a technical document is introduced by a general XML authoring tool.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.9C
• /
• pp.871-876
• /
• 2005

In this paper, we propose an improved partial response maximum likelihood (PRML) detection scheme that has an adaptive equalizer and can be applied in the asymmetric optical recording system with high-density. We confirmed that the proposed PRML detector improves detection performance. In addition, we implemented the detector by Verilog HDL. The adaptive equalizer is composed of tap coefficient updating unit using LMS algorithn and FIR filter. FIR filter is implemented by the transposed direct form architecture for high speed operation. Viterbi detector is implemented by the register exchange method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2019.05a
• /
• pp.29-32
• /
• 2019

The development of Information and Communication Technology facilitates exchange of information and communication between system in ships or between ships and land facilities, thereby improving the efficiency of their work. However, these changes in the working environment of companies and ships increased the likelihood of cyber security incidents occurance like unauthorized access to company and ship systems or infection of malicious code, which results in significant safety, environmental and business damage to company and ships. Therefore, a cyber-risk-based approach was required to identify and respond to an increasing cyber threats. In this paper, the analysis of maritime cyber security status and guidelines for establishment of maritime cyber security system are provided.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.8 no.2
• /
• pp.69-78
• /
• 2013

As vehicles become more intelligent for safety and convenience of drivers, in-vehicle networking systems such as controller are network (CAN) have been widely used due to increasing number of electronic control unit (ECU). Recently, FlexRay was developed to replace CAN protocol in chassis networking systems, to remedy the shortage of transmission capacity and unsatisfactory real-time transmission delay of conventional CAN. However, it is difficult for vehicle network designers to calculate platform configuration registers (PCR) and determine a base cycle or slot length of FlexRay. To assist vehicle network designers for designing FlexRay cluster, this paper presents automatic field bus exchange format (FIBEX) generation algorithm from CANdb information, which is de-facto standard database format for CAN. To design this program, structures of FIBEX, CANdb and relationship among PCR variables are analyzed.

• ETRI Journal
• /
• v.19 no.3
• /
• pp.186-201
• /
• 1997

In this paper, a home location register (HLR) for CDMA mobile communication system (CMS) is introduced. It stores the mobile station (MS) subscribers locations and supplementary service information. Call processing procedures for HLR are developed to receive and store subscriber's location coming from mobile exchange (MX) during the location registration, and to transfer subscriber's location and supplementary service information to the MX during the mobile-terminated call setup. For fast call processing by increasing database access speed, a memory-resident database management system is devised. For Easy and secure HLR operation, administration and maintenance functions and overload control mechanisms are implemented. Designed HLR hardware platform is expandable and flexible enough to reallocated software blocks to any subsystems within the platform. It is configurable according to the size of subscribers. An authentication center (AC) is developed on the same platform. It screens the qualified MS from the unqualified. The calls to and from the unqualified MS are rejected in CMS. To authenticate the MS, the AC generates a new authentication parameter called "AUTHR" using shared secret data (SSD) and compared it with the other AUTHR received from the MS. The MC also generates and stores seed keys called "A-keys" which are used to generate SSDs. The HLR requirements, the AC requirements, software architecture, hardware platform, and test results are discussed.