• Journal of KIISE
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• v.42 no.4
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• pp.434-441
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• 2015

Next generation memory technologies, which we denote as 'new memory', have both non-volatile and byte addressable properties. These characteristics are expected to bring changes to the conventional computer system structure. In this paper, we propose a fast boot technique for hybrid main memory architectures that have both new memory and DRAM. The key technique used for fast booting is write-tracking. Write-tracking is used to detect and manage modified data detection and involves setting the kernel region to read-only. This setting is used to trigger intentional faults upon modification requests. As the fault handler can detect the faulting address, write-tracking makes use of the address to manage the modified data. In particular, in our case, we make use of the MMU (Memory Management Unit) translation table. When a write occurs to the boot completed state, write-tracking preserves the original state of the modified address of the kernel region to a particular location, and execution continues. Upon booting, the fast booting process restores the preserved data to the original kernel region allowing rapid system boot-up. We develop the fast booting technique in an actual embedded board equipped with new memory. The boot time is reduced to less than half a second compared to around 15 seconds that is required for the original system.

• Journal of KIISE:Software and Applications
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• v.32 no.12
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• pp.1271-1282
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• 2005

Recently, PC-based control is incredibly developed in the industrial control field, but it is difficult for PLC programming in PC. Therefore, I need to develop the softeware PLC, which support the international PLC programming standard(IECl131-3) and can be applied to diverse control system by using C language. In this paper, I have developed the ISPLC(Intelligent Agent System based Software Programmable Logic Controller). In ISPLC system, LD programmed by a user which is used over $90\%$ among the 5 PLC languages, is converted to IL, which is one of intermediate codes, and IL is converted to the standard C rode which can be used in a commercial editor such as Visual C++. In ISPLC, the detection of logical error in high level programming(C) is more eaier than PLC programming itself The study of code conversion of LD->IL->C is firstly tried in the world as well as KOREA. I developed an execution engine with a good practical application. To show the effectiveness of the developed system, 1 applied it to a practical case, a real time traffic control(RT-TC) system. ISPLC is minimized the error debugging and programming time owing to be supported by windows application program.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.83-93
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• 2013

Recently, the SURF algorithm, which is conjugated for object tracking system as part of many computer vision applications, is a well-known scale- and rotation-invariant feature detection algorithm. The SURF, due to its high computational complexity, there is essential to develop a hardware accelerator in order to be used on an IP in embedded environment. However, the SURF requires a huge local memory, causing many problems that increase the chip size and decrease the value of IP in ASIC and SoC system design. In this paper, we proposed a way to design a SURF algorithm in hardware with greatly reduced local memory by partitioning the algorithms into several Sub-IPs using external memory and a DMA. To justify validity of the proposed method, we developed an example of simplified object tracking algorithm. The execution speed of the hardware IP was about 31 frame/sec, the logic size was about 74Kgate in the 30nm technology with 81Kbytes local memory in the embedded system platform consisting of ARM Cortex-M0 processor, AMBA bus(AHB-lite and APB), DMA and a SDRAM controller. Hence, it can be used to the hardware IP of SoC Chip. If the image processing algorithm akin to SURF is applied to the method proposed in this paper, it is expected that it can implement an efficient hardware design for target application.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.35-40
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• 2024

In this paper, we validate the practicality of the OnePIC app implemented in the previous study by analyzing the execution and storage performance. The OnePIC app is a camera app that allows you to get a photo with a desired focus after taking photos focused on various places. To evaluate performance, we analyzed distance focus shooting time and object focus shooting time in detail. The performance evaluation was measured on actual smartphone. Distance focus shooting time for 5 photos was around 0.84 seconds, the object detection time was around 0.19 seconds regardless of the number of objects and object focus shooting time for 5 photos was around 4.84 seconds. When we compared the size of a single All-in-JPEG file that stores multi-focus photos to the size of the JPEG files stored individually, there was no significant benefit in storage space because the All-in-JPEG file size was subtly reduced. However, All-in-JPEG has the great advantage of managing multi-focus photos. Finally, we conclude that the OnePIC app is practical in terms of shooting time, photo storage size, and management.

• Journal of KIISE:Information Networking
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• v.35 no.2
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• pp.99-111
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• 2008

In recent years, the needs for WLANs(Wireless Local Area Networks) technology which can access to Internet anywhere have been dramatically increased particularly in SOHO(Small Office Home Office) and Hot Spot. However, unlike wired networks, there are some unique characteristics of wireless networks. These characteristics include the burst packet losses due to unreliable wireless channel. Note that burst packet losses, which occur when the distance between the wireless station and the AP(Access Point) increase or when obstacles move temporarily between the station and AP, are very frequent in 802.11 networks. Conversely, due to burst packet losses, the performance of 802.11 networks are not always as sufficient as the current application require, particularly when they use TCP at the transport layer. The high packet loss rate over wireless links can trigger unnecessary execution of TCP congestion control algorithm, resulting in performance degradation. In order to overcome the limitations of WLANs environment, MAC-layer LDA(Loss Differentiation Algorithm)has been proposed. MAC-layer LDA prevents TCP's timeout by increasing CRD(Consecutive Retry Duration) higher than burst packet loss duration. However, in the wireless channel with high packet loss rate, MAC-layer LDA does not work well because of two reason: (a) If the CRD is lower than burst packet loss duration due to the limited increase of retry limit, end-to-end performance is degraded. (b) energy of mobile device and bandwidth utilization in the wireless link are wasted unnecessarily by Reducing the drainage speed of the network buffer due to the increase of CRD. In this paper, we propose a new retransmission module based on Cross-layer approach, called BLD(Burst Loss Detection) module, to solve the limitation of previous link layer retransmission schemes. BLD module's algorithm is retransmission mechanism at IEEE 802.11 networks and performs retransmission based on the interaction between retransmission mechanisms of the MAC layer and TCP. From the simulation by using ns-2(Network Simulator), we could see more improved TCP throughput and energy efficiency with the proposed scheme than previous mechanisms.