Estimation of Markovian Transition Probabilities for Pavement Deterioration Forecasting

Kiyoshi Kobayashi,도명식,한대석 대한토목학회 2010 KSCE JOURNAL OF CIVIL ENGINEERING Vol.14 No.3

While it is impossible to estimate when a road section will collapse, the understanding of road section deterioration can help asset managers predict the condition of road sections and take appropriate actions for rehabilitations. Deterioration forecasting modeling is an essential element for an efficient pavement management system. Although the Pavement Management System (PMS) has been introduced and operated for optimal road maintenance since the late 1980s in Korea, some problems for accurate prediction of road deterioration remain due to the quality of pavement performance data and the different pavement structural, material and environmental conditions. In this paper, a methodology to estimate the Markov transition probability model is presented to forecast the deterioration process of road sections. The deterioration states of the road sections are categorized into several ranks and the deterioration processes are characterized by hazard models. The Markov transition probabilities between the deterioration states,which are defined by the non-uniform or irregular intervals between the inspection points in time, are described by the exponential hazard models. Furthermore, in order to verify the validity of the proposed method, the applicability of the estimation methodology presented in this paper is investigated by using the empirical surface data set of the national highway in Korea.

21세기의 합의형성 과제와 일본 사례

KOBAYASHI Kiyoshi(小林潔司) 대한토목학회 2003 대한토목학회지 Vol.51 No.4

Non-Steady State Gas Permeation Measurements of $TiO_2$-Doped YSZ

Kobayashi, Kiyoshi,Yamaguchi, Shu,Iguchi, Yoshiaki The Korean Ceramic Society 2000 The Korean journal of ceramics Vol.6 No.2

Mobilities of electrons ($\mu_p$) and holes ($\mu_p$) in 2, 5, and 10 mol% $TiO_2$-doped yttria stabilized zirconia (TD-YSZ) have been estimated by a non-steady state gas permeation method using models proposed by Weppner and Maruyama. Values of $\mu_n$ and $\mu_p$ were found to be closed to those in non-doped YSZ reported earlier. The concentration of electrons and holes were calculated from $\mu_n$ and $\mu_p$ values and the partial conductivities of electrons and holes measured by a dc-polarization method. The concentration of electrons at unit oxygen partial pressure increased with increasing $TiO_2$concentration, while the hole concentration was almost independent of $TiO_2$concentration.

Partial Conductivity of YSZ Doped with 10 mol% $TiO_2$

Kobayashi, Kiyoshi,Kai, Yukiharu,Yamaguchi, Shu,Kawashima, Tsuyoshi,Iguchi, Yoshiaki The Korean Ceramic Society 1998 The Korean journal of ceramics Vol.4 No.2

Using Hebb-Wagner's asymmetric cell, partial conductivities of holes and electrons in yttria stabilized zirconia doped with 10 mol% TiO2 have been estimated by a dc polarization measurement. The current interrruption method and ac impedance measurements have been also made to evaluate the ionic conductivity and to examine the consistency of the partial conductivities. Partial conductivities of electrons(σn) and holes (σp) were found to be pro-peortional to -1/4 and 1/4 power of partial pressure of oxygen gas, respectively, except for σn at reducing conditions. In comparison with 5 mol% doped YSZ, σn was found to increase with the increase of TiO2 concentration, but σp stayed at almost a constant value.

Section-based Multifunctional Calibration Method for Pavement Deterioration Forecasting Model

한대석,Kiyoshi Kobayashi,도명식 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.2

Deterioration forecasting modeling is an essential element for an efficient pavement management system. The HDM-4 (Highway Development & Management-4) model developed by the World Bank is widely distributed to more than 100 countries around the world. However, many users often point out problems related to calibration limitations, and question the reliability of their results due to the extremely large number of variables, and difficulty in the calibration procedure of deterioration models in the HDM-4. The current calibration method based on the Network-based approach which was introduced by the HDM-4 developer and has several limitations in describing the precise deterioration progress, and practical application. In fact, many HDM-4 users often give up implementation due to these reasons. To mitigate these problems, this paper suggests an improved calibration method for the HDM-4 deterioration models relevant to the deterioration speed and shape of the curve. The benefits are not limited to only high precision calibration, but also easy application by minimum data, and covering problems on incomplete pavement inventory data which are considered the most serious problems in the application of the HDM-4. The validity of the suggested methods was empirically shown through experience with the national highways in Korea. This paper could be a good reference for the implementation of the current HDM-4 model, as well as its future improvement.

Criteria for the Development and Improvement of PMS Models

한대석,Kiyoshi Kobayashi 대한토목학회 2013 KSCE Journal of Civil Engineering Vol.17 No.6

When road agencies seek to introduce, evaluate or improve their Pavement Management System (PMS), there is often confusion due to lack of a long-term PMS development strategy. In fact, many road agencies have relied on others’ experiences or ready-made software not well suited to their own PMS situation. Obviously, a PMS model should be developed step by step with a well-grounded long-term PMS development plan. As fundamental research on PMS, this paper aims to foster sustainable development of PMS models by suggesting criteria for the development of PMS. As contents of the criteria, 1) a general PMS framework, 2) the standardization of PMS capability level, 3) a definition of PMS functions and 4) data requirements and management are treated as the main focus of research. These criteria are expected to serve as a useful guideline for the initial introduction, self-examination, and extension of PMS capabilities. While this research may be usefully applied to individual cases, a much more important goal is to establish compatibility among PMS models. Mitigating heterogeneity among PMS models can greatly benefit the PMS world. In addition, the criteria could serve as a foundation for various undertakings in PMS research.

Hypothesis Testing on Divers' Rational Expectations : An Experimental Approach

Myungsik Do,Kiyoshi Kobayashi 대한토목학회 2000 KSCE journal of civil engineering Vol.4 No.1

A Study on an Optimal Resource Allocation Algorithm for Next Generation Mobile Satellite Communication Systems

Nakahira, Katsuya,Kobayashi, Kiyoshi,Ohata, Kohei,Ueba, Masazumi 통신위성우주산업연구회 2004 Joint Conference on Satellite Communications Vol.2004 No.-

To yield a large communication capacity in future mobile satellite communication systems, a multi-beam system must be employed that has extremely high levels of frequency reuse. This paper proposes a novel resource allocation algorithm for multi-beam satellite communication systems that can dynamically offer the virtually maximum communication capacity. The algorithm optimizes frequency bandwidth, satellite transmission power, modulation level and coding rate to each beam to deal with the ever changing traffic distribution considering interference between beams. First, the optimal resource allocation is found by evaluating capacities for all possible resource allocation patterns. Although, this primitive search takes a huge amount of computer calculation power, the achieved communication capacities are higher than with conventional ones such as fixed resource system. In addition, the results of analysis clarify the the optimal condition by which all clusters have the same bandwidth allocation ratio. Second, we propose an optimal resource allocation algorithm utilizing the aforementioned condition as a constraint. By using our algorithm, which is based on sequential quadratic programming, the calculation amount can be drastically reduced. It is confirmed that the algorithm allocate the same bandwidth as that by the amount can be drastically reduced. It is confirmed that the algorithm allocate the same bandwidth as that by the primitive search method for varieties of traffic model. This means that the preposed algorithm is applicable for multi-beam satellite resource allocation.

Route Navigation State-Contingent Road Pricing

Myungsik Do,Kiyoshi Kobayashi 대한토목학회 2000 KSCE journal of civil engineering Vol.4 No.3

Multicarrier/Multirate modem providing channel de-assemble and assemble functions

Tanabe, Kazuhiro,Kobayashi, Kiyoshi,Ohata, Kohei,Ueba, Masazumi 통신위성우주산업연구회 2001 Joint Conference on Satellite Communications Vol.2001 No.-

A satellite communication system for enterprise Intranets must be able to support simultaneous multi-point connections among dispersed locations and to allocate satellite channels with the required data rates of each of the connections independently. To meet these requirements, the Multicarrier/Multirate Group Modem (MCMRM) for earth stations is proposed that can process multiple and various rate. MCMRM has the following features. 1. Supports simultaneous communications with hundreds of channels. (Maximum 768) 2. The prototype modem is roughly the same size of as the conventional single carrier modem. 3. To secure flexibility and scalability, the developed modem consists of independent modules. 4. Supports the allocation of bandwidth required over dispersed frequency bands, even if continuous frequency band is not available. MCMRM consists of a multi-rate filter bank and a group modem implemented on several FPGAs controlled by a timesharing system. Evaluations show that MCMRM has even higher BER performance than a conventional single carrier modem. This paper describes the architecture and processing method of MCMRM and performance evaluation results.