受験番号：36IPE021

問１．
In recent years, the development of laminated 3D printers, which is astructuring method that involves building modeling bodies (structures) stacked in layers
by using a 3D printing technology, has been progressing both domestically andinternationally in the construction field. The material used for the laminated 3D
printer is basically cementitious material, and mortar kneaded by a mixer is pumped andsupplied to a 3D modeling machine. Construction using the laminated 3D printer canbuild the structures stacked in layers without any formwork and thus is expected to behighly superior to conventional concrete construction in terms of labor savings, design
flexibility, safety, and the like.
[0003]In order to put such a construction method into practical use in the future, it isnecessary to consider the pumpability of the material, the self-standing properties of thematerial immediately after it is discharged from a nozzle to form stacked modelingbodies (structures), and the surface properties of stacked bodies after curing, in addition
to the development and improvement of 3D printers.
[0004]The building of stacked modeling bodies (structures) with high construction
accuracy primarily requires the development of materials with high self-standing
performance, and the machine development such as the positioning accuracy and speedof a nozzle and the ejection amount of the material. Further, it requires the structural
performance that enables the built structure (structure form) to exhibit strength enoughto withstand various external forces.
問２[0037]
Each of the high-frequency inverter 12 in the power transmission section 1 andthe high-frequency rectifier circuit 22 in the power receiving section 2 is composed offour reverse-conducting power semiconductor switches (Q1-Q4) such as MOSFETs orIGBTs that constitute a full bridge circuit. Specifically, it is composed of a pair ofinverter legs in which high-side switching elements (Q1, Q3) and low-side switchingelements (Q2, Q4) are connected in series, while a reverse parallel diode is connected inparallel to each of the switching elements. The high-frequency inverter 12 in thepower transmission section 1 uses a phase-shift pulse-width modulation method that can1

adjust the high-frequency output only by phase control of the drive timing of theswitching elements (Q1 to Q4).
[0038]The voltage smoothing capacitor 24 connected in parallel to the battery 21 in
the power receiving section 2 suppresses ripples that occur after the rectification
performed by the high-frequency rectifier circuit 22 and smoothes a signal so that it iscloser to direct current.
[0039]
Each of the resonant circuit 13 on the power transmission side and the resonant
circuit 23 on the power receiving side is composed of a reactor (L1, L2) and a variablecapacitor (C1, C2). An ultrasonic transducer using a piezoelectric material such as a
BLT is a capacitor-type load (C-type load) and thus it may be combined with a reactor
only to realize a resonant circuit.
[0040]As mentioned above, BLT can be used as a powerful ultrasonic transducer
because it can achieve very large stress amplitude due to the pre-compressive stressapplied by bolts.
In addition, BLT has high mechanical strength and highelectrical/acoustic conversion efficiency.
Thus, BLT is suitable for ultrasonicnon-contact power transmission in the sea. Although BLT has an inherent mechanicalresonant frequency, it can achieve extremely large stress amplitude by being driven at ornear its resonant frequency.
問３
1.
A position estimation system that estimates a position of a radio receiver in agiven space based on received signal strengths when the radio receiver receives radio
waves transmitted from three or more radio transmitters within the space, the position
estimation system comprising:an acquisition unit for acquiring information about the received signal strengthsof the radio waves received from the three or more radio transmitter;a generating unit for generating a first vector based on the information
corresponding to at least three of the three or more radio transmitters, the first vector
including, as an element, a distance between each of the at least three radio transmittersand the radio receiver; andan estimation unit for estimating the position of the radio receiver based on
similarity between the first vector and a second vector corresponding to a predetermined
position in the space, the second vector including, as an element, a distance between
2each of the at least three radio transmitters and the predetermined position.
2.

The position estimation system according to claim 1,
wherein the second vector is generated for each of a plurality of positions on apredetermined planar region in the space, andwherein the estimation unit estimates the position of the radio receiver basedon similarity between the first vector and the second vector corresponding to each of theplurality of positions.
3.

The position estimation system according to claim 1 or 2,
wherein the second vector is generated for each of a plurality of different
combination sets of radio transmitters, each set including at least three radio transmittersof the three or more radio transmitters,
wherein the generating unit generates the first vector for each of the plurality ofsets, andwherein the estimation unit estimates the position of the radio receiver basedon similarity between the first vector and the second vector for each of the plurality ofsets.

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