Joonhyouk Jang

Learn More
As the demand for the high-speed processing of mass data increases, the use of in-memory systems is increasing. In-memory systems enable data to be accessed in memory, thereby allowing for its high-speed processing. However, as the size and volume of the data increases, its recovery speed from a replicated server gets slower. In this paper, we propose a(More)
The portion of HFT in market is growing rapidly. To process hundreds of thousands of orders per second which are requested by algorithms trading, not by humans, trading systems are required to equip high performance computer, network devices, and efficient software solutions. To achieve performance requirements, financial trading software processes data in(More)
Recently, many studies have been conducted on key-value store as a platform for distributed storage services. A key-value store manages data as key-value pairs using hash tables. In this paper, we propose a hybrid hash table management technique to improve the performance of single nodes in a key-value store. The proposed scheme uses cuckoo hashing and(More)
A major challenge in a virtual machine scheduler is the I/O performance of a network-based or a disk-based application running on a virtual machine. The existing virtual machine scheduler does not achieve good I/O performance when many active virtual CPUs exist. In this study, we propose a novel scheme that uses a modified Credit scheduler for I/O-intensive(More)
The proliferation of ubiquitous computing has led to the development of various types of sensor devices for human-computer interaction (HCI). However, the availability of developer tools is lacking in comparison with the development of sensor devices. This shortcoming has been partially addressed by the introduction of open source hardware but it is(More)
In recent times, with the advancing of the graphics processing unit (GPU), parallel computing using general-purpose computing on GPU (GPGPU) is expanding. This is achieved through a processing speed faster than those of traditional computing environments across many fields, such as science, medicine, engineering, and analysis. However, there are many(More)
Data stores in distributed systems maintain backup servers for data recovery. Most existing data stores use non-volatile storage to store backup data. However, high-performance systems may require the use of the main memory for backup storage instead of disks due to the performance gap between the disks and the memory. In this paper, we present an expected(More)
Using InfiniBand technologies, the performance of key-value stores can be greatly improved because of RDMA features and the ultra-low latency of InfiniBand. However, maximizing the benefits of InfiniBand for key-value stores is still challenging because of the data consistency problem between RDMAs and CPU-aware memory accesses. In this paper, we propose a(More)
In this paper, we propose a steganography-based software watermarking scheme to protect Android applications from software piracy. Considering the resource limitations in mobile devices, it is difficult to apply previous software watermarking schemes in mobile applications. To decrease the watermarking overhead in a watermarking scheme, such as a slowdown(More)