In this paper, we propose a chromatic adaptation model based on the adapting degree according to the level of adapting luminance and chromaticity in various surround illuminants. In the proposed model, first maximum adapted cone responses are calculated through the estimation of adapting degree for viewing conditions then corresponding colors are reproduced from original colors using the ratio of maximum adapted cone responses between different viewing conditions. The purpose of this study is to produce chromatic adaptation transform applied to environment-adaptive color display system. As a result, our proposed model can give better estimation performance than prior models and be embodied easily as a linear model in display systems. So it is confirmed that the implemented system can predict corresponding-color data very well under a variety of viewing conditions.

Conventional CPM signals employ information sequence with time-unlimited phase shaping pulse (PSP) to achieve power and bandwidth efficient transmission. On the contrary, information sequence using time-limited PSP was believed to produce power-wasting data-independent discrete spectral lines in CPM spectra, and was suggested to be avoided. In this paper, we revisit this problem and adopt the time-limited PSP to replace the one with time-unlimited, it turns out to have an alternative solution to the CPM scheme. We first modify the spectral computing formula for the CPM with time-limited PSP (or CPM-TL) from conventional CPM formula and show that the discrete spectral lines appeared in the power density spectrum of CPM-TL signals can be diminished or become negligible by appropriately choosing PSP. We also show that this class of CPM can use any real number modulation index (h) and the resultant trellis structure of CPM guarantees the maximum constraint length allowed by the number of states in the MLSD receiver. Finally, the energy-bandwidth performance of CPM using time-limited PSP is investigated and compared with conventional CPM with time-unlimited PSP. From numerical results we show that, under the same number of states in the MLSD receiver and bandwidth occupancy, this subclass of CPM could outperform the conventional CPM up to 6dB coding gain, for h<1, in many cases.

An on-chip SIDO DC-DC boost converter core that can be used for both battery and solar cell operating applications is proposed. The converter is able to supply a current of up to around 30mA with an on-chip driver and more than 100mA by using an off-chip power MOS driver. The cross regulation problem was solved by inserting an extra cycle. Efficiencies of 85% and 84% were achieved for each driving mode. Complicated maximum power point tracking (MPPT) controls are available for a solar cell operation. An embedded micro-computer can be used to calculate a complicated algorithm. The converter exploits 99% of the expected maximum power of the solar cell. The converter protects the leak current that flows through the solar cell when there is no light. The proposed protection circuits reduce the leak current by three orders of magnitude without any performance loss.

This paper describes how to design matching structures to improve the frequency characteristics of one-dimensional finite periodic structures. In particular, it deals with one-dimensional finite superlattices. A downhill simplex method is used to determine some of the structural parameters of the matching structure. Numerical examples show that this method is effective in improving the frequency characteristics of finite superlattices.

In information retrieval from printed images considering the use of mobile devices, the correction of geometrical deformation and lens distortion is required, posing a heavy computational burden. In this paper, we propose a method of reducing the computational burden for such corrections. This method consists of improved extraction to find a line segment of a frame, the reconsideration of the interpolation method for image correction, and the optimization of image resolution in the correction process. The proposed method can reduce the number of computations significantly. The experimental result shows the effectiveness of the proposed method.

This paper describes a novel technique to replace some of the driven elements in an array antenna with parasitic elements. First, the antenna characteristics are studied by simulation for a basic unit array with one driven and two parasitic elements. The entire antenna is backed with a flat reflector to conform to practical applications. The parasitic elements are excited by the neighboring driven elements through the electromagnetic coupling effect. It is shown that at the optimal coupling condition, the radiation patterns are almost identical with those of an array antenna whose elements are all driven without coupling. The simulation result is confirmed by performing an experiment at 5.8GHz (λ =51.7mm). Finally, a 12-element array is formed by combining four unit arrays. The simulation results show that the maximum antenna gain is 19.4dBi, indicating that there is no penalty with respect to the antenna gain of a fully driven 12-element array. Therefore, the array antenna can be considerably simplified by replacing 67% of its elements with parasitic elements.

LTE-Advanced supports asymmetric carrier aggregation (CA) to achieve flexible bandwidth allocation by applying different numbers of component carriers (CCs) between the downlink and uplink. This paper experimentally clarifies the achievable downlink throughput performance when uplink control information (UCI) feedback mechanism using the physical uplink shared channel (PUSCH), which enables minimization of the UCI overhead while maintaining the required reception quality, is applied in asymmetric CA. The laboratory experimental results show that the stable reception quality control of the channel quality information (CQI) with the target block error rate (BLER) of 10-1 to 10-2 is achieved irrespective of the average received signal-to-noise power ratio (SNR) when the control offset parameter of approximately 1.25 is used. We also show that the achievable downlink throughput when the CQI error is considered is almost the same as that in no CQI error case. Furthermore, based on the experimental results in a real field environment, a suburban area of Yokosuka city in Japan, we confirm stable adaptive modulation and coding (AMC) operation including target BLER control of the CQI on the PUSCH in asymmetric CA. The field experimental results also show that when CA with 5 CCs (90-MHz bandwidth) and 2-by-2 rank-2 multiple-output multiple-input (MIMO) multiplexing are employed in the downlink, the peak throughput of approximately 640Mbps is achieved even considering the CQI error.

Electromagnetic scattering and radiation in cylindrical electromagnetic bandgap (EBG) structure is analyzed. The radiated field from a line source placed inside the eccentric configuration of the cylindrical EBG structure and plane wave incident on the cylindrical EBG structure is numerically studied based on the method proposed by the authors in their early papers. Using the developed formulation, it is shown first time that when the cylindrical EBG is illuminated by plane wave of particular resonance frequencies, the field are strongly enhanced or shaded inside the cylindrical EBG structure and this effect depends on the angle of incidence of the plane waves. We give a deep physical insight into explanation of this phenomenon based on the Lorentz reciprocity relation for cylindrical structures.

This paper proposes an inter-prediction method for the upcoming video coding standard named HEVC (High Efficiency Video Coding). The HEVC offers an inter-prediction framework called local intensity compensation which represents a current block by a linear combination of some reference blocks. The proposed method calculates weight coefficients of the linear combination by using sparse representation. Experimental results show that the proposed method increases prediction accuracy in comparison with other methods.

This paper proposes a secure wireless network system required for an ambient information society; it forms a privacy zone wherein terminals can securely communicate secret information using an arbitrary general radio channel. For this system, we introduce a scheme using a side-information from a special node. The information is used as an encryption key so that the detectable region of the key defines a privacy zone. We implement the scheme on the basis of IEEE 802.15.4 and realize the world's first ambient network platform with the above functionality. An experiment and demonstration show the effectiveness of the proposed system.

In this letter, we investigate the performance of cooperative decode-and-forward multiple-input multiple-output relaying system using orthogonal space-time block codes with piecewise-linear (PL) receiver over correlated Nakagami-m fading channels for integer values of m. We derive the closed-form expression for the exact bit error rates of binary phase shift keying signals. The analytical expression is validated through numerical results. It is shown that the performance of PL receiver outperforms that of conventional maximal ratio combining receiver.

In this paper, we examine additive homomorphic encryptions in the discrete logarithm setting. Recently, Wang et al. proposed an additive homomorphic encryption scheme by modifying the ElGamal encryption scheme [Information Sciences 181(2011) 3308-3322]. We show that their scheme allows only limited number of additions among encrypted messages, which is different from what they claimed.

We consider the minimum feedback vertex set problem for some bipartite graphs and degree-constrained graphs. We show that the problem is linear time solvable for bipartite permutation graphs and NP-hard for grid intersection graphs. We also show that the problem is solvable in O(n2log 6n) time for n-vertex graphs with maximum degree at most three.

In an orthogonal frequency division multiplexing (OFDM) communication system, two users use the same frequencies and number of sub-carriers so as to increase spectrum efficiency. When the codewords employed by them form a Golay complementary sequence (CS) mate, this system enjoys the upper bound of peak-to-mean envelope power ratio (PMEPR) as low as 4. This letter presents a construction method for producing S16-QAM and A16-QAM Golay CS mates, which arrives at the upper bound 4 of PMEPR. And when used as a Golay CS pair, they have an upper bound 2 of PMEPR, which is the same ones in both [18] and [17]. However, both cannot produce such mates.

In tooth contour extraction there is insufficient intensity difference in x-ray images between the tooth and dental bone. This difference must be enhanced in order to improve the accuracy of tooth segmentation. This paper proposes a method to improve the intensity between the tooth and dental bone. This method consists of an estimation of tooth orientation (intensity projection, smoothing filter, and peak detection) and PCA-Stacked Gabor with ellipse Gabor banks. Tooth orientation estimation is performed to determine the angle of a single oriented tooth. PCA-Stacked Gabor with ellipse Gabor banks is then used, in particular to enhance the border between the tooth and dental bone. Finally, active contour extraction is performed in order to determine tooth contour. In the experiment, in comparison with the conventional active contour without edge (ACWE) method, the average mean square error (MSE) values of extracted tooth contour points are reduced from 26.93% and 16.02% to 19.07% and 13.42% for tooth x-ray type I and type H images, respectively.

This paper presents a VLSI design of a Tomlinson-Harashima (TH) precoder for multi-user MIMO (MU-MIMO) systems. The TH precoder consists of LQ decomposition (LQD), interference cancellation (IC), and weight coefficient multiplication (WCM) units. The LQ decomposition unit is based on an application specific instruction-set processor (ASIP) architecture with floating-point arithmetic for high accuracy operations. In the IC and WCM units with fixed-point arithmetic, the proposed architecture uses an arrayed pipeline structure to shorten a circuit critical path delay. The implementation result shows that the proposed architecture reduces circuit area and power consumption by 11% and 15%, respectively.

This paper introduces our developed noise robust speech communication techniques and describes its implementation to a smart info-media system, i.e., a small robot. Our designed speech communication system consists of automatic speech detection, recognition, and rejection. By using automatic speech detection and recognition, an observed speech waveform can be recognized without a manual trigger. In addition, using speech rejection, this system only accepts registered speech phrases and rejects any other words. In other words, although an arbitrary input speech waveform can be fed into this system and recognized, the system responds only to the registered speech phrases. The developed noise robust speech processing can reduce various noises in many environments. In addition to the design of noise robust speech recognition, the LSI design of this system has been introduced. By using the design of speech recognition application specific IC (ASIC), we can simultaneously realize low power consumption and real-time processing. This paper describes the LSI architecture of this system and its performances in some field experiments. In terms of current speech recognition accuracy, the system can realize 85-99% under 0-20dB SNR and echo environments.

To understand human emotion, it is necessary to be aware of the surrounding situation and individual personalities. In most previous studies, however, these important aspects were not considered. Emotion recognition has been considered as a classification problem. In this paper, we attempt new approaches to utilize a person's situational information and personality for use in understanding emotion. We propose a method of extracting situational information and building a personalized emotion model for reflecting the personality of each character in the text. To extract and utilize situational information, we propose a situation model using lexical and syntactic information. In addition, to reflect the personality of an individual, we propose a personalized emotion model using KBANN (Knowledge-based Artificial Neural Network). Our proposed system has the advantage of using a traditional keyword-spotting algorithm. In addition, we also reflect the fact that the strength of emotion decreases over time. Experimental results show that the proposed system can more accurately and intelligently recognize a person's emotion than previous methods.

We describe an In-Cell Projected Capacitive Touch Panel in a display using IGZO TFT technology. The prototype demonstrates high signal-to-noise ratio (SNR) and pen input operation. The possibility of enlarging the display size beyond current limits makes this a highly promising approach for In-Cell Capacitive touch panels.

Morphemes, which are obtained from morphological parsing, and statistical sub-words, which are derived from data-driven splitting, are commonly used as the recognition units for speech recognition of agglutinative languages. In this letter, we propose a discriminative approach to select the splitting result, which is more likely to improve the recognizer's performance, for each distinct word type. An objective function which involves the unigram language model (LM) probability and the count of misrecognized phones on the acoustic training data is defined and minimized. After determining the splitting result for each word in the text corpus, we select the frequent units to build a hybrid vocabulary including morphemes and statistical sub-words. Compared to a statistical sub-word based system, the hybrid system achieves 0.8% letter error rates (LERs) reduction on the test set.