Showing papers by "Waseda University published in 1999"
TL;DR: In this paper, the authors proposed a Lab-on-a-Chip (LOC) for the first time, which is based on the idea of Labon-A-Chip.
Abstract: 9.1 Lab-on-a-Chip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 9.1.
581 citations
TL;DR: In this paper, 4,6-dimethoxy-1, 3,5-triazin-2(1H)-one was obtained by esterification of caiboxylic acids with DMTMM in methanol, ethanol, isopropy1 alcohol, or t-butyl alcohol.
403 citations
01 Jan 1999
TL;DR: A basic control method of whole body cooperative dynamic biped walking that uses trunk or trunk-waist cooperative motion to compensate for three-axis moment generated not only by the motion of the lower-limbs planned arbitrarily but by the time trajectory of the hands planned arbitrarily is proposed.
Abstract: The authors have focused on the bipedal humanoid robot expected to play an active role in human living space, through studies on an anthropomorphic biped walking robot. As the first stage of developing a bipedal humanoid robot, the authors developed the human-size 35 active DOF bipedal humanoid robot "WABIAN" and the human-size 41 active DOF bipedal humanoid robot "WABIAN-R". The authors also proposed a basic control method of whole body cooperative dynamic biped walking that uses trunk or trunk-waist cooperative motion to compensate for three-axis (pitch, roll and yaw-axis) moment generated not only by the motion of the lower-limbs planned arbitrarily but by the time trajectory of the hands planned arbitrarily. Using these systems and the control method, normal biped walking (forward and backward), dynamic dance, waving arms and hip, dynamic carrying of a load using its arms, and trunk-waist cooperative dynamic walking are achieved.
399 citations
01 Nov 1999
TL;DR: In this article, the limit case of Sobolev's inequalities was studied in RN and the best exponents αN were shown to be false for all α ∈ (0, αN), αN = Nω N−1 (ωN−1 is the surface area of the unit sphere in RN ), and αN is defined by exp(ξ) − N−2 ∑ j=0 1 j! ξ.
Abstract: We study Trudinger type inequalities in RN and their best exponents αN . We show for α ∈ (0, αN ), αN = Nω N−1 (ωN−1 is the surface area of the unit sphere in RN ), there exists a constant Cα > 0 such that ∫ RN ΦN α( |u(x)| ‖∇u‖LN (RN ) ) N N−1 dx ≤ Cα ‖u‖NLN (RN ) ‖∇u‖N LN (RN ) (∗) for all u ∈W 1,N (RN ) \ {0}. Here ΦN (ξ) is defined by ΦN (ξ) = exp(ξ) − N−2 ∑ j=0 1 j! ξ . It is also shown that (∗) with α ≥ αN is false, which is different from the usual Trudinger’s inequalities in bounded domains. 0. Introduction In this note, we study the limit case of Sobolev’s inequalities; suppose N ≥ 2 and let D ⊂ R be an open set. We denote by W 1,N 0 (D) the usual Sobolev space, that is, the completion of C∞ 0 (D) with the norm ‖u‖W 1,p 0 (D) = ‖∇u‖p+‖u‖p. Here ‖u‖p = (∫
284 citations
TL;DR: In this paper, three concepts of concern to manufacturing management; agile manufacturing, adaptable production and lean production are described and compared within the context of the modern competitive situation in Japan, and a survey of Japanese firms is described where the concepts are explored through a number of questions concerned with strategy, action programmes and performance measures.
279 citations
TL;DR: It is demonstrated that induction of mPer1 mRNA is required for light- or glutamate-induced phase shifting, suggesting that the acute induction ofmPer1 RNA in the SCN after light exposure is involved in light- induced phase shifting of the overt rhythm.
Abstract: mPer1, a mouse gene, is a homolog of the Drosophila clock gene period and has been shown to be closely associated with the light-induced resetting of a mammalian circadian clock. To investigate whether the rapid induction of mPer1 after light exposure is necessary for light-induced phase shifting, we injected an antisense phosphotioate oligonucleotide (ODN) to mPer1 mRNA into the cerebral ventricle. Light-induced phase delay of locomotor activity at CT16 was significantly inhibited when the mice were pretreated with mPer1 antisense ODN 1 hr before light exposure. mPer1 sense ODN or random ODN treatment had little effect on phase delay induced by light pulses. In addition, glutamate-induced phase delay of suprachiasmatic nucleus (SCN) firing rhythm was attenuated by pretreatment with mPer1 antisense ODN, but not by random ODN. The present results demonstrate that induction of mPer1 mRNA is required for light- or glutamate-induced phase shifting, suggesting that the acute induction of mPer1 mRNA in the SCN after light exposure is involved in light-induced phase shifting of the overt rhythm.
269 citations
TL;DR: In this paper, the dry gel conversion (DGC) technique has been used to synthesize a wide variety of microporous crystals, such as pure silica, metallosilicates, and aluminophosphates, using tetraethylammonium hydroxide.
Abstract: Recently the dry gel conversion (DGC) technique, where a hydrogel is dried and the resultant dry gel is converted into microporous crystals in steam or in a mixed vapor of steam and organic structure-directing agents (SDAs), has been developed. It has been shown that a wide variety of microporous crystals, pure silica microporous crystals, aluminosilicates, metallosilicates, and aluminophosphates, can be synthesized using the DGC method. Remarkable results have been reported in the synthesis of BEA types zeolites, namely aluminosilicate, titaniumsilicate, zincosilicate, and borosilicate with BEA topology, using tetraethylammonium hydroxide, a commercially available SDA. It has also been found that zeolite OU-1, probably analogous to SSZ-31 and NCL-1, is formed via phase transformation from BEA. Dense zeolite coatings like membranes are possible using this method. Characteristics of the DGC method are discussed in detail.
264 citations
TL;DR: The first public Japanese speech corpus for large vocabulary continuous speech recognition (LVCSR) is JNAS (Japanese Newspaper Article Sentences) as mentioned in this paper, which contains utterances of about 45, 000 sentences as a whole with each speaker reading about 150 sentences.
Abstract: In this paper we present the first public Japanese speech corpus for large vocabulary continuous speech recognition (LVCSR) technology, which we have titled JNAS (Japanese Newspaper Article Sentences). We designed it to be comparable to the corpora used in the American and European LVCSR projects. The corpus contains speech recordings (60 h) and their orthographic transcriptions for 306 speakers (153 males and 153 females) reading excerpts from the newspaper's articles and phonetically balanced (PB) sentences. This corpus contains utterances of about 45, 000 sentences as a whole with each speaker reading about 150 sentences. JNAS is being distributed on 16 CD-ROMs.
262 citations
TL;DR: It is shown that ethanol opens G-protein-activated, inwardly rectifying K+ (GIRK) channels, which has important implications for inhibitory regulation of neuronal excitability and heart rate.
Abstract: Ethanol affects many functions of the brain and peripheral organs. Here we show that ethanol opens G-protein-activated, inwardly rectifying K + (GIRK) channels, which has important implications for inhibitory regulation of neuronal excitability and heart rate. At pharmacologically relevant concentrations, ethanol activated both brain-type GIRK1/2 and cardiac-type GIRK1/4 channels without interaction with G proteins or second messengers. Moreover, weaver mutant mice, which have a missense mutation in the GIRK2 channel, showed a loss of ethanol-induced analgesia. These results suggest that the GIRK channels in the brain and heart are important target sites for ethanol.
255 citations
TL;DR: In this article, the equations of motion of compressible viscous and heat-conductive gases in an exterior domain in ℝ3 were considered and an optimal decay estimate for solutions to the nonlinear problem was given.
Abstract: We consider the equations of motion of compressible viscous and heat-conductive gases in an exterior domain in ℝ3. We give the L_q−L_p estimates for solutions to the linearized equations and show an optimal decay estimate for solutions to the nonlinear problem.
239 citations
TL;DR: The true image area that can be used for recording microscopic objects in hybrid holographic microscopy can be increased by elimination of the conjugate image and the zero-order image, so two shutters and one phase modulator were added to the electro-optical holographic recording system.
Abstract: The true image area that can be used for recording microscopic objects in hybrid holographic microscopy can be increased by elimination of the conjugate image and the zero-order image. We therefore added two shutters and one phase modulator to the electro-optical holographic recording system so that we could change the recording parameters and evaluate four methods of eliminating the conjugate image and the zero-order image. We found that the methods that use only the phase modulator require the recording of fewer holograms than do the methods that use the shutters and also provide reconstructed images that are less noisy.
TL;DR: Results suggest that Pin1 is required for cell cycle progression from G(0) arrest as well as mitosis progression in normal mammalian cells.
TL;DR: In this article, 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) was quantitatively synthesized by coupling of 2-chloro-4, 6-dimethoxy and 1, 3, 5-triazine and N-methylmethylmorpholine in THF, and fully characterized.
TL;DR: In this paper, the emission mechanisms of strained InGaN quantum wells (QWs) were shown to vary depending on the well thickness L and InN molar fraction x, where Si-doping was found to improve the interface quality and surface morphology, resulting in an efficient carrier transfer from high to low bandgap energy portions of the well.
Abstract: The emission mechanisms of strained InGaN quantum wells (QWs) were shown to vary depending on the well thickness L and InN molar fraction x . The QW resonance energy was shifted to lower energy by the quantum confined Stark effect (QCSE) due to the internal piezoelectric field, F PZ . The absorption spectrum was modulated by QCSE and quantum-confined Franz–Keldysh effect (QCFK) for the wells, in which, for the first approximation, the product of F PZ and L (potential drop across the well) exceeds the valence band discontinuity, Δ E V . In this case, dressed holes are confined in the triangular potential well formed at one side of the well. This produces apparent Stokes-like shift (vertical component). The QCFK further modulated the absorption energy for the wells with L greater than the three dimensional free exciton Bohr radius, a B . For the wells having high InN content ( F PZ × L >Δ E V , Δ E C ), electron and hole confined levels drop into the triangular potential wells formed at opposite sides of the wells, which reduces the wavefunction overlap. Doping of Si in the barriers partially screens F PZ resulting in a smaller Stokes-like shift, shorter recombination decay time, and higher emission efficiency. Si-doping was found to improve the interface quality and surface morphology, resulting in an efficient carrier transfer from high to low bandgap energy portions of the well. Effective in-plane localization of carriers in quantum disk size potential minima, which are produced by nonrandom alloy potential fluctuations enhanced by the large bowing parameter and F PZ , produces confined e–h pair whose wavefunctions are still overlapped. Their excitonic features are pronounced provided that L a B and F PZ × L E V (quantized exciton). Several cw laser wafers exhibit stimulated emission from these energy tail states even at room temperature.
TL;DR: Taxol, an anticancer substance, was adsorbed into FSM-type mesoporous silicas with the pore sizes larger than 1.8 nm, while Taxol was not adaption into the channels with pore size less than 2.6 nm as discussed by the authors.
Abstract: Taxol, an anticancer substance, was adsorbed into FSM-type mesoporous silicas with the pore sizes larger than 1.8 nm, while it was not adsorbed into the channels with the pore size less than 1.6 nm, indicating that mesoporous silicas have a molecular sieving property for relatively large molecules. The adsorption behavior of Taxol depended on the solvents; Taxol was not adsorbed into mesoporous silicas when methanol or acetone was used but was adsorbed when dichloromethane or toluene was used. The adsorption behavior of Taxol is discussed on the basis of the solubility parameters of the solvents. The proton-acceptor solubility parameter (δa) is a predominant factor in this liquid−solid partition system. The adsorption−desorption of an extract from yew needles was performed using the mesoporous silica and several elution solvents. In the adsorption, many components including Taxol were adsorbed into mesoporous silica. When the desorption of the extract components adsorbed into the mesoporous silica was per...
TL;DR: Improvements in the ability of old adults to perform steady submaximal isometric and anisometric contractions were associated with a reduced level of muscle activation, especially during the lengthening contractions.
Abstract: When old adults participate in a strength-training program with heavy loads, they experience an increase in muscle strength and an improvement in the steadiness of submaximal isometric contractions...
TL;DR: In this paper, the specific heat coefficient of Co 2 was measured at low-temperatures to determine the magnitude of the electronic specific-heat coefficient, and it was shown that it is a strongly correlated electron system, where the strong correlation probably comes from the lowdimensionality and the frustrated spin structure.
Abstract: The specific heat of $(\mathrm{N}\mathrm{a},\mathrm{C}\mathrm{a}){\mathrm{Co}}_{2}{\mathrm{O}}_{4}$ is measured at low-temperatures to determine the magnitude of the electronic specific-heat coefficient $\ensuremath{\gamma},$ in an attempt to gain an insight into the origin of the unusually large thermoelectric power of this compound. It is found that $\ensuremath{\gamma}$ is as large as $\ensuremath{\sim}48 {\mathrm{m}\mathrm{J}/\mathrm{m}\mathrm{o}\mathrm{l}\mathrm{K}}^{2},$ which is an order of magnitude larger than $\ensuremath{\gamma}$ of simple metals. This indicates that $(\mathrm{N}\mathrm{a},\mathrm{C}\mathrm{a}){\mathrm{Co}}_{2}{\mathrm{O}}_{4}$ is a strongly-correlated electron system, where the strong correlation probably comes from the low-dimensionality and the frustrated spin structure. We discuss how the large thermopower and its dependence on Ca doping can be understood with the strong electron correlations.
TL;DR: In this paper, thermally responsive polymeric micelles composed of poly( N -isopropylacrylamide- co -N, Ndimethylacryamide)- b -poly( d,l -lactide) were prepared by dialysis from its dimethylacetamide solution against water.
TL;DR: In this article, a cross-linked poly(N-isopropylacrylamide) (PIPAAm) hydrogel-modified surfaces were prepared by polymerization of IPAAm in the presence of crosslinker on the substrates on which an azo polymerization initiator was covalently bonded.
Abstract: Cross-linked poly(N-isopropylacrylamide) (PIPAAm) hydrogel-modified surfaces were prepared to investigate the effects of a three-dimensionally cross-linked structure of PIPAAm layers on both wettability changes and hydrophobic interactions with hydrophobic solutes in response to temperature changes The temperature-responsive surface was prepared by polymerization of IPAAm in the presence of cross-linker on the substrates on which an azo polymerization initiator was covalently bonded The PIPAAm hydrogel-modified surface showed temperature-responsive hydrophilic/hydrophobic surface property alterations as demonstrated by a large and discontinuous wettability changes in a range of 27−32 °C, a slightly lower temperature range than the phase transition temperature for soluble PIPAAm in aqueous media This implies that the dynamic motion in response to temperature for PIPAAm segments in the modified hydrogel is restricted due to the cross-linked structure The effect of the three-dimensional PIPAAm structure
TL;DR: In this article, a transmittance spectrum of a single quantum well structure with a well width of 5 nm at room temperature was observed and the total internal electric field strength in the well was estimated from the absorption peak position based on a simple calculation, neglecting excitons.
Abstract: Excitonic absorption was observed in a transmittance spectrum of AlGaN/GaN/AlGaN single quantum well structure with a well width of 5 nm at room temperature. The total internal electric field strength in the well was about 0.73 MV/cm, which was estimated from the absorption peak position based on a simple calculation, neglecting excitons. The observation is clearly due to the quantum-confined Stark effect. While excitonic absorption was clearly observed even in such a high internal field, no light emission was detected under a He-Cd laser excitation at temperatures ranging from room temperature to T = 10 K. Light emission accompanied by a blue shift of the emission peak and an increase of emission intensity was observed under higher excitation power density. The obvious conclusion in the present case is that the presence of a high internal electric field in the well is a disadvantage for light emission.
TL;DR: Physiological studies on the interstitial cells of Cajal are reviewed, in support of the hypothesis by THUNEBERG (1982) that they function as a pacemaker in the digestive tract and a mediator transmitting impulses from the nerve terminals to the smooth muscle cells.
Abstract: Recent studies on the interstitial cells of Cajal (ICC) have determined ultrastructural criteria for the identification of these previously enigmatic cells. This review deals with the electron microscopic findings obtained by the author’s research group in different tissue regions of the gut in mice, rats and guinea-pigs, comparing these with reports from other groups in different species and in humans. ICC are characterized by the following morphological criteria: numerous mitochondria, abundant intermediate filaments and large gap junctions which connect the cells with each other and with smooth muscle cells. Due to their location in the gut and the specific species, the ICC are markedly heterogeneous in appearance, ranging from cells closely resembling smooth muscle cells to those similar to fibroblasts (Table 1). Nevertheless, the above-mentioned morphological features are shared by all types of ICC and serve in identifying them. Recent discoveries on a significant role of c-kit in the maturation of the ICC and their specific immunoreactivity to anti-c-Kit antibody have confirmed the view that the ICC comprise an independent and specific entity of cells. This view is reinforced by the findings of the author’s group that the ICC characteristically possess vimentin filaments and are stained with the zinc iodide-osmium tetroxide method which provides a staining affinity similar to methylene blue, the dye used in the original work by CAJAL (1911). Developmental studies indicate that the ICC are derived from a non-neuronal, mesenchymal origin. This paper further reviews advances in the physiological studies on the ICC, in support of the hypothesis by THUNEBERG (1982) that they function as a pacemaker in the digestive tract and a mediator transmitting impulses from the nerve terminals to the smooth muscle cells.
TL;DR: A real-time beat-tracking system that detects a hierarchical beat structure in musical audio signals without drum-sounds and a method of detecting chord changes that does not require chord names to be identified is proposed.
TL;DR: In this paper, an electric double layer capacitor (EDLC) was prepared with an activated carbon powder electrode with poly(vinylidene fluoridehexafluoropropylene) (PVdF-HFP) based gel electrolyte.
Abstract: An electric double layer capacitor (EDLC) was prepared with an activated carbon powder electrode with poly(vinylidene fluoridehexafluoropropylene) (PVdF-HFP) based gel electrolyte. Ethylene carbonate (EC) and propylene carbonate (PC) were used as plasticizer and tetraethylammonium tetrafluoroborate (TEABF4) was used as the supporting electrolyte. An optimized gel electrolyte of PVdF-HFP/PC/EC/TEABF4 5 23/31/35/11 mass ratio exhibited high ionic conductivity of 5 3 10 23 S cm 21 , high electrode capacitance, and good mechanical strength. An electrode consisting of activated carbon (AC) with the gel electrolyte as the bind er (AC/PVdF-HFP based gel, 7/3 mass ratio) showed a higher specific capacitance and a lower ion diffusion resistance within the electrode than a carbon electrode, prepared with PVdF-HFP binder without plasticizer. This suggests that an electrode mixed with the gel electrolyte has a lower ion diffusion resistance inside the electrode. The highest specific capacitance of 123 F g 21 was achieved with an electrode containing AC with a specific surface area of 2500 m 2 g 21 . A coin-type EDLC cell with optimized components showed excellent cycleability exceeding 10 4 cycles with ca. 100% coulombic efficiency achieved when charging and discharging was repeated between 1.0 and 2.5 V at 1.66 mA cm 22 .
TL;DR: In this paper, a double-crucible system was used to measure surface velocities of thermal and solutal Marangoni convection in In-Ga-Sb melt.
TL;DR: In this article, a kaolinite/methanol intercalation compound was synthesized by guest displacement reaction of a Kaolin/N-methyl-formamide interalation compound with methanol.
TL;DR: In this paper, the resistivity and thermopower of NaCo were measured and analyzed, and it was shown that the excess Na is unlikely to supply carriers and decreases effective conduction paths in the sample.
Abstract: The resistivity and thermopower of ${\mathrm{Na}}_{1+x}{\mathrm{Co}}_{2}{\mathrm{O}}_{4}$ and ${\mathrm{Na}}_{1.1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{Co}}_{2}{\mathrm{O}}_{4}$ are measured and analyzed. In ${\mathrm{Na}}_{1+x}{\mathrm{Co}}_{2}{\mathrm{O}}_{4},$ whereas the resistivity increases with x, the thermopower is nearly independent of x. This suggests that the excess Na is unlikely to supply carriers, and decreases effective conduction paths in the sample. In ${\mathrm{Na}}_{1.1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{Co}}_{2}{\mathrm{O}}_{4},$ the resistivity and the thermopower increase with x, and the ${\mathrm{Ca}}^{2+}$ substitution for ${\mathrm{Na}}^{+}$ reduces the majority carriers in ${\mathrm{NaCo}}_{2}{\mathrm{O}}_{4}.$ This means that they are holes, which is consistent with the positive sign of the thermopower. Strong correlation in this compound is evidenced by the peculiar temperature dependence of the resistivity.
TL;DR: The shape, distribution, and ultrastructural features of interstitial cells of Cajal of different tissue layers and organs of the rat and guinea‐pig digestive tract were described and compared with the corresponding cells in other species including mice, dogs, and humans.
Abstract: The shape, distribution, and ultrastructural features of interstitial cells of Cajal (ICC) of different tissue layers and organs of the rat and guinea-pig digestive tract were described and compared with the corresponding cells in other species including mice, dogs, and humans, as reported in the literature. By light microscopy, the best marker for ICC appeared to be immunoreactivity for c-Kit. Ultrastructurally, ICC were characterized by the presence of many mitochondria, bundles of intermediate filaments, and gap junctions, which linked ICC with each other. However, ICC were morphologically heterogeneous and had particular features, depending on their tissue and organ location and species. ICC in the deep muscular plexus of the small intestine and in the submuscular plexus of the colon were the most like smooth muscle cells, and had a distinct basal lamina and numerous caveolae. In contrast, ICC of Auerbach's plexus at all levels of the gastrointestinal tract were the least like smooth muscle cells. They most closely resembled unremarkable fibroblasts. ICC within the circular muscle layer were intermediate in form. In addition to the tissue specificity, some organ and species specificity could be distinguished. The structural differences between ICC may be determined by their microenvironment, including the effects of mechanical force, type of nerve supply, and spacial relationship with smooth muscle cells.
TL;DR: In this article, the structure and reactivities of platinum-blues and the related amidate-bridged platinumIII are discussed and a zigzag chain structure of the platinum blues having Pt-Pt bonds is described.
Abstract: Publisher Summary This chapter discusses structures and reactivities of platinum-blues and the related amidate-bridged platinumIII. Compounds platinumIII is usually unstable and can be isolated only in complexes with certain special ligands. Monomeric PtIII complex is very rare and so far only one well-characterized complex is known, in contrast to the now increasing knowledge of PtIII dinuclear complexes. The chapter mentions amidate-bridged dinuclear PtIII complexes and multinuclear PtII,III mixed-valent complexes, generally called “platinumblues.” The novel zigzag chain structures of the platinum blues having Pt-Pt bonds, redox chemistry between PtII and PtIII in these complexes electron spin resonance (ESR) spectra of Pt III, 195Pt-NMR of PtIII, and various stoichiometric and catalytic reactions with organic molecules mostly involving PtII/III redox reactions are summarized in the chapter. The antitumor inactive compounds are relatively stable and are disrupted only to dinuclear amidate-bridged compounds. The advantage of these complexes is that each Pt complex is isolated in pure form, and their crystal structure is known.
TL;DR: In this paper, scanning tunneling microscopy (STM) was performed, using Au(111) as the substrate, to examine the structure of the adsorbed layers of the additive molecules, and the results revealed that the nature of adsorption is fundamentally different for the two different additives; i.e., saccharin is physical and reversible whereas thiourea undergoes irreversible chemisorption.
Abstract: During the course of our recent work performed to develop an electroplated CoNiFe ternary alloy with high saturation magnetic flux density and low coercivity for use in magnetic recording heads, it was observed that two common sulfur‐containing additives, saccharin and thiourea, behave differently with respect to the dependence of sulfur inclusion and coercivity of the alloy film on the additive concentration in the plating bath To understand the cause of this difference, scanning tunneling microscopy (STM) was performed, using Au(111) as the substrate, to examine the structure of the adsorbed layers of the additive molecules The result revealed that the nature of adsorption is fundamentally different for the two different additives; ie, the adsorption of saccharin is physical and reversible, whereas thiourea undergoes irreversible chemisorption This finding is consistent with the known behaviors of the two additives in the electroplating of nickel In this paper the different effects of saccharin and thiourea in the electrodeposition of CoNiFe alloy are interpreted based on the STM results and relevant information available in the literature on the electrodeposition of nickel © 1999 The Electrochemical Society All rights reserved
Proceedings Article•
01 Jan 1999
TL;DR: A robot who converses with multi-person using his multi-modal interface realizes human friendly multi- person conversation system by utilizing face direction recognition, gesture recognition, sound direction recognition), speech recognition and gestural expression.
Abstract: This paper describes a robot who converses with multi-person using his multi-modal interface. The multi-person conversation includes many new problems, which are not cared in the conventional oneto-one conversation: such as information flow problems (recognizing who is speaking and to whom he is speaking / appealing to whom the system is speaking), space information sharing problem and turn holder estimation problem (estimating who is the next speaker). We solved these problems by utilizing multi-modal interface: face direction recognition, gesture recognition, sound direction recognition, speech recognition and gestural expression. The systematic combination of these functions realized human friendly multi-person conversation system.