http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Modified pilot selection for channel estimation of systematic polar coded MIMO-OFDM
Koya Watanabe,Shun Kojima,Takashi Akao,Masato Katsuno,Kazuki Maruta,안창준 한국통신학회 2019 ICT Express Vol.5 No.4
This paper proposes a modified pilot selection for channel estimation of systematic polar coded MIMO-OFDM. Polar codes provably achieve the theoretical limit for communication systems and systematic polar codes generate the codeword that has the same value of information bit. Using this property, an efficient channel estimation scheme was proposed; values of some information bits are fixed to zeros or ones and utilized for pilot symbols. Similarly, we also can fix values of some frozen bit as zeros or ones by exploiting features of the encoding generator. By combining these advantages, pilot signals are selected from the systematic polar coded symbols themselves and we do not need add and insert pilot symbols just to estimate the channel. Leveraging this, we apply the proposed systematic polar coding scheme to MIMO-OFDM system under frequency selective fading channel.
Reducing channel spatial correlation by rotating planar antenna array
Takashi Akao,Koya Watanabe,Shun Kojima,Masato Katsuno,Kazuki Maruta,안창준 한국통신학회 2019 ICT Express Vol.5 No.4
This paper newly proposes a direct antenna array control approach to reduce channel spatial correlation for multiuser spatial multiplexing. Conventional rectangular arrays can form three dimensional beams and have superior signal separation performance compared to linear arrays. However, when the arrival angles of some signals are close, the signal separation (interference cancellation) performance deteriorates since the projection points onto horizontal/vertical axes of several antenna elements overlap and spatial resolution along each axis is degenerated. The key proposal is to improve signal separation performance by mechanically changing the positional relationship of antenna elements. The proposed scheme can achieve better Bit Error Rate (BER) performance by searching the optimal antenna rotation angle.
SIRT1 in Type 2 Diabetes: Mechanisms and Therapeutic Potential
Munehiro Kitada,Daisuke Koya 대한당뇨병학회 2013 Diabetes and Metabolism Journal Vol.37 No.5
The prevalence of type 2 diabetes mellitus (T2DM) has been increasing worldwide. Therefore, a novel therapeutic strategy by which to prevent T2DM is urgently required. Calorie restriction (CR) can retard the aging processes, and delay the onset of numerous age-related diseases including diabetes. Metabolic CR mimetics may be therefore included as novel therapeutic targets for T2DM. Sirtuin 1 (SIRT1), a NAD+-dependent histone deacetylase that is induced by CR, is closely associated with lifespan elongation under CR. SIRT1 regulates glucose/lipid metabolism through its deacetylase activity on many substrates. SIRT1 in pancreatic β-cells positively regulates insulin secretion and protects cells from oxidative stress and inflammation, and has positive roles in the metabolic pathway via the modulation in insulin signaling. SIRT1 also regulates adiponectin secretion, inflammation,glucose production, oxidative stress, mitochondrial function, and circadian rhythms. Several SIRT1 activators, including resveratrol have been demonstrated to have beneficial effects on glucose homeostasis and insulin sensitivity in animal models of insulin resistance. Therefore, SIRT1 may be a novel therapeutic target for the prevention of T2DM, implicating with CR. In this review, we summarize current understanding of the biological functions of SIRT1 and discuss its potential as a promising therapeutic target for T2DM.
Autophagy: A Novel Therapeutic Target for Diabetic Nephropathy
Shinji Kume,Daisuke Koya 대한당뇨병학회 2015 Diabetes and Metabolism Journal Vol.39 No.6
Diabetic nephropathy is a leading cause of end stage renal disease and its occurance is increasing worldwide. The most effective treatment strategy for the condition is intensive treatment to strictly control glycemia and blood pressure using renin-angiotensin system inhibitors. However, a fraction of patients still go on to reach end stage renal disease even under such intensive care. New therapeutic targets for diabetic nephropathy are, therefore, urgently needed. Autophagy is a major catabolic pathway by which mammalian cells degrade macromolecules and organelles to maintain intracellular homeostasis. The accumulation of damaged proteins and organelles is associated with the pathogenesis of diabetic nephropathy. Autophagy in the kidney is activated under some stress conditions, such as oxidative stress and hypoxia in proximal tubular cells, and occurs even under normal conditions in podocytes. These and other accumulating findings have led to a hypothesis that autophagy is involved in the pathogenesis of diabetic nephropathy. Here, we review recent findings underpinning this hypothesis and discuss the advantages of targeting autophagy for the treatment of diabetic nephropathy.